Police returned to gather more evidence Friday from the home where Sally Lopez and Peter Mountain were murdered.
Police say they are following several leads in the effort to search for whoever is responsible for killing the couple. They add that the attack does not appear to be random.
Autopsies conducted Thursday showed the couple had been stabbed and shot to death inside their southwest suburban home.
The slayings have left neighbors on edge.
"After the facts came out that both victims were not only shot but stabbed and bludgeoned, that's concerning," said neighbor Scott Batzel.
Friday morning, Burbank police officers canvassed again in the 6400-block of West 83rd Place hoping for any leads that may lead to the couple's killer.
"An officer came by, and he asked me if I had seen anything," said neighbor Martin Calderon. "I said no and then I mentioned that I had a camera but it's not hooked up, so I really couldn't help them much."
Witnesses say 79-year-old Mountain and 80-year-old Lopez were found unresponsive in a bedroom by a relative who called police to the home around 9:30 a.m. Wednesday.
"It must have happened overnight," said Calderon.
According to the Cook County medical examiner's office, Mountain died of multiple gunshot wounds and a stab wound to the neck. Lopez suffered the same in addition to blunt force trauma to the head.
Police issued a community alert and in a statement said:
"We want to express to Burbank residents that this is an isolated incident. There was no sign of forced entry nor was burglary or robbery a motive."
The South Suburban Major Crimes Task Force is assisting with the investigation.
"I've lived here my entire life, and this is certainly concerning, but it hasn't changed how I feel about living here in Burbank," said Batzel.
More than three dozen detectives are working the case, but so far there have been no arrests and no one is in custody.