Hernandez was reported missing by his stepmother after she told police she last saw him at their home before she took a shower and fell asleep.
WATCH: Missing boy's mother speaks out
"It's a 5-year-old child, they don't just vanish into thin air," said Jamie Orr, the missing boy's biological mother, told KWCH.
Orr spent the past week with other volunteers searching Wichita parks for any sign of Lucas.
"On Thursday we went back to Chisholm because we were called off on Monday, and I never realized - I'm not from here - how huge that park is," she said.
Orr said her biggest fear is hearing the investigation may be slowing down. Last week, Wichita police said they'd stop searching parks unless a new tip prompted them to go back.
"We need those tips coming in. If they're not coming in, we got nothing to go on," Orr said.
A Texas-based group, EquuSearch, was approved by Wichita police to do their own search this weekend.
EquuSearch founder Tim Miller said his group has assisted in over 1,700 missing persons cases, including high profile cases like Natalee Holloway.
"We do a lot of stuff still with our horses. We do stuff with ATVs, ground searches. We do a tremendous amount of stuff with the boats, sonar equipment, our drone planes," Miller said.
Miller said he understands the pain Orr and Lucas' family is going through after his own daughter went missing many years ago. Her body was found 17 months later.
"I remember every minute of that 17 months - of the helplessness, the hopelessness, the loneliness. And I just made a promise to God I would never leave a family alone if there's anything I can ever can do and here we are," Miller said.
As of Tuesday, KAKE reports that EquuSearch has not yet located anything associated with the case.
WATCH: Missing boy's stepmother appears in court
A Wichita police report shows that drugs or narcotics are suspected in the child endangerment case that happened on Feb. 16, one day before 5-year-old Lucas Hernandez was reported missing.
Emily Glass was charged with one count of endangering a one-year-old child who police confirm is Glass' daughter. She made her first appearance before a judge on Monday wearing a yellow uniform, which signifies an inmate on suicide watch.
Glass, 26, was arrested and booked last week for suspicion of endangering two children, a 1-year-old girl and 5-year-old, Lucas. The incident was discovered on Feb. 21, while police were investigating the Lucas Hernandez case.
After the case was presented to the Sedgwick County District Attorney's Office, Glass was charged with only endangering her 1-year-old daughter.
The criminal complaint claims that Glass "unlawfully, knowingly and unreasonably" caused or permitted a one-year-old child "to be placed in a station in which the child's life, body or health may be endangered" on Feb. 16th between 4 p.m. and 6 p.m. The police report obtained by KAKE shows that Glass was suspected of using drugs/narcotics.
WATCH: Police announce arrest of missing boy's stepmother
Glass was the last person to see the Wichita boy alive. She called police 10 days ago to say the Lucas had disappeared from their home.
Working with the FBI, Wichita police have searched a number of local parks, including Cottonwood Park.
"We continue to investigate this, I know it is on the minds and hearts of many in our community," said Officer Davidson, Wichita Police Department.
A team of volunteers helped to cover more than 21 acres at a different park filled with dense brush. Speculation of the child's whereabouts have been overshadowed by reports raising questions about the child's home-life.
A HISTORY OF VIOLENCE
The father and stepmother of a 5-year-old Kansas boy who has been missing since Saturday had a volatile relationship, according to police records.
Emily Glass, 26, the stepmother of Lucas Hernandez, was arrested Wednesday and jailed on two counts of endangering a child involving Lucas and another child. She remained jailed Thursday and has not been officially charged.
Glass reported the boy missing Saturday, saying she last saw him at their home before she took a shower and fell asleep. Despite extensive searches, the boy has not been found. Deputy Chief Gavin Seiler said police still hope to find the boy alive.
Police records detail several incidents at two addresses where the couple lived in the past two years, The Wichita Eagle reported .
One police report said Glass held a wooden ax handle during an April 2016 argument in which the boy's father, Jonathan Hernandez, suffered a bloody nose and other injuries. Glass had bruises on the side of her head and accused him of slapping her. The report says officers couldn't determine the primary aggressor. Glass was convicted of misdemeanor disorderly conduct. The same charge against Hernandez was dismissed.
The reports detail two other incidents where police went to the couple's home in response to reports of arguments. In a November 2016 incident, an officer reported injuries on Jonathan Hernandez's face where he said Glass had slapped him and she admitted to pushing him.
Police have not said where Jonathan Hernandez was when the boy was reported missing.
Glass had not had a first court appearance and it was unclear if she has an attorney.
Family members have told Wichita media outlets since the disappearance that they were concerned Lucas was being abused and had reported the possible abuse to the Kansas Department of Children and Families last year.
WATCH: Missing boy's father: 'I just want him to come home'
Johnathan Hernandez told KAKE-TV Wednesday that he was upset his family members had talked to the media because it took focus away from finding his son.
"Now, if you want to bring that up later that's fine," Hernandez said. "That's a whole separate issue. I think it's taking away from what's happening and I don't appreciate it. Not from my family, not from strangers."
He said he still believes his son is alive and he is focused on finding him.
On Wednesday, Wichita police arrested the boy's stepmother, 26-year-old Emily Glass, on two counts of child endangerment. Glass was the last person to see her 5-year-old stepson, Lucas Hernandez, before he went missing.
"The charges are related to new information gathered during this investigation," Deputy Police Chief Gavin Seiler said Wednesday afternoon. "Officers and investigators have been working on this case non-stop."
Seiler said the two child endangerment counts related to Lucas and a 1-year-old child. He did not release details on the alleged incidents, but said more charges could be coming.
Wichita police have said that Glass last saw Lucas when she then took a shower and fell asleep. Officers were notified around 6:15 p.m. that the boy was missing.
"We hope that we are able to find Lucas," Seiler said.
The news of the arrest isn't surprising to some of the child's family members. Lucas's great aunt, Sally Rasmussen, released photos only to KAKE showing bruises on Lucas's body.
Rasmussen says the photos were taken in May 2017. They show bruises on the child's face, arm, back and buttocks. Rasmussen says the photos were included in a report she filed with the Kansas Department for Children and Families last year. The boy's father spoke about those allegations as well.
"I'm sorry that they did and that really pisses me off. Only because it seems like it's about something else and it's not happening now," Hernandez said. "Now, if you want to bring that up later that's fine. That's a whole separate issue. I think it's taking away from what's happening and I don't appreciate it. Not from my family, not from strangers."
WATCH: Tips on missing boy lead investigators to park
Meanwhile, Wichita police and the Federal Bureau of Investigation continue to search for a missing 5-year-old boy who was last seen Saturday afternoon.
KAKE reports Lucas Hernandez was last seen around 3 p.m. on Saturday near his home in the 600 block of South Edgemoor. Wichita police said the boy's stepmother last saw Lucas at around 3 p.m. Saturday when she then took a shower and fell asleep. Officers were notified around 6:15 p.m. that the boy was missing.
The Federal Bureau of Investigation has deployed its Child Action Rapid Deployment team to assist in the search, and the Wichita Police Department has activated its Emergency Operation Command Center.
Lucas has brown hair and brown eyes, weighs 60 pounds and is four feet tall. He was last known to be wearing black sweats, white socks and a gray shirt with a bear on it. He's a Pre-K student at Beech Elementary School.
Officer Charley Davidson with the Wichita Police Department said Tuesday morning that about 100 law enforcement officials are helping in the search for Lucas.
"We are going to be there as long as it takes," Officer Davidson said. "Right now, our concern is to find Lucas."
Since the weekend, teams have searched Chisholm Creek Park, Dr Glen Day Park, Harrison Park and the boy's neighborhood. Authorities are planning more searches, but Davidson did not say where.
Although people want to start search parties, Davidson said the department has adequate resources to search. He said the best thing people can do is submit tips by calling (316) 383-4661.
RELATIVE SAYS SHE SAW SIGNS OF ABUSE BEFORE BOY'S DISAPPEARANCE
Lucas' great-aunt Sally Rasmussen, who lives in New Mexico, told ABC News that she saw marks on the boy's arms and on his cheek in a photo she saw of him last May.
Rasmussen, who said she's worked with at-risk youth before, said she is familiar with the possible signs of abuse and reported the marks to Kansas Child Protective Services.
Rasmussen said relatives grew more concerned when Lucas and his father, Johnathan Hernandez, visited New Mexico in November. She said they told her they saw more signs of abuse and reported them to authorities in New Mexico.
However, Rasmussen does not believe Lucas' father hurt his son.
"He loves his son dearly!" Rasmussen wrote in a Facebook message to ABC News.
She added that she believes Hernandez, who often travels out of state for work, was out of town working when Lucas disappeared. According to police, Lucas' stepmother told investigators she last saw him in his bedroom just before she took a shower and fell asleep. Police were called to the home about three hours later.
The New Mexico Children, Youth, and Families Department told ABC News that its cases are confidential and did not confirm whether it has an open case involving Lucas.
The Kansas Department for Children and Families, of which Child Protective Services is a part, said it couldn't share any information on its cases either but expressed worry for Lucas.
"We share the public's concern regarding Lucas Hernandez," Theresa Freed, communications director for Kansas DCF, said in a statement to ABC News. "In the event the agency has information, we will share it with law enforcement, assisting them as requested."
Wichita police confirmed in a media briefing Monday that they have had contact with the family before, but did not elaborate on the nature of that contact.
Authorities said they have as many as 100 officers working the case and have searched the Hernandez home as well as Wichita's Chisholm Trail Park, Grove Park and Harrison Park using horses, dogs and drones, but have found no sign of Lucas.
At a prayer vigil on Monday night, Lucas' father told ABC affiliate KAKE he was thankful for the community's help.
"I think it's good to see people in this community treating Lucas like he's their child," Hernandez said. "This is a serious thing and we want him home."
The family is cooperating with the investigation, authorities said.
ABC News has reached out to other relatives of Lucas, but did not immediately receive a response.
ABC News and the Associated Press contributed to this report.