Sengstacke is the grandson of late Chicago Defender publisher John Sengstacke.
Police questioned Sengstacke for most of the day at the Chicago Police Department's 21st District headquarters on the South Side. The Secret Service said the suspect never posed any direct threat to Obama. He was arrested after breaching the intense security that now surrounds Obama's home in his once-quiet Hyde Park neighborhood.
The Sengstacke family released a statement Tuesday night saying they're passionate supporters of Obama and Omhari Sengstacke had no intent to harm anyone.
"There's a lot of buzz around the neighborhood, a lot of excitement around the neighborhood," said Monique Bridgewater, Hyde Park resident.
For Bridgewater, it has been an exciting summer. Her apartment at Hyde Park Avenue and Greenwood is just across the intersection from Senator Barack Obama's house and its 24-hours-a-day security.
"Parking is a little troublesome. But other than that, I understand it so I accept it," Bridgewater said.
But accepting it means Secret Service agents and Chicago police will investigate thoroughly any suspicious activity.
A Secret Service spokesman said the suspect in Tuesday morning's incident appeared intoxicated when he first appeared at the security perimeter before dawn. When he did not move on after being told to do so, he was arrested. It was during a subsequent search of his car parked nearby that police say they found a handgun.
Obama's neighbors that ABC7 interviewed said they are getting used to the security, which includes having to show identification to reach their homes.
"At the beginning we were not used to it. Now it's ok, we show our ID. Sometimes, they know we are residents, so we don't have any problem," said Fatima Barros, Obama's neighbor.
"You could walk down the street and wait for the bus in front of his house, and now you can't," said Lewis Brennan, neighborhood resident.
"It's always been safe," said Roy Coleman. "Usually, if there's a problem, you see University of Chicago police as the first ones to show up and Chicago police almost immediately after it."
Obama, who attended fundraisers until late Monday night, was likely in the house with his family while the man was being arrested outside. As is its practice regarding security matters, the Obama campaign would not comment on the incident.
Late Tuesday afternoon, a Chicago police spokeswoman confirmed a bulletproof vest was also found in the suspect's car. It is illegal to have body armor in Chicago if you are also in possession of an illegal firearm.