(CNN) -- Alabama authorities closed in on the attic of a Montgomery home late Monday, believing they had trapped the man accused of killing three people and wounding three others near Auburn University.
Police had already used "a powerful dose" of tear gas in an attempt to force out the suspect, Montgomery Mayor Todd Strange told reporters. Montgomery Public Safety Director Chris Murphy said a tactical squad had taken control of the home's ground floor and heard noise, including coughing, in the attic.
"We feel like he's hunkered down in there," Murphy said. Investigators have tried to talk to the man, "and that has not been responded to," he said.
Investigators can't conclusively say the person in the attic was 22-year-old Desmonte Leonard, now wanted on three counts of capital murder. But Strange said the call that brought police to the scene "indicated that a person that looked like the suspect might be in this house," and two other callers reported someone who looked like Leonard was in the area, Strange said.
Montgomery County Sheriff D.T. Marshall said the owner of the house returned home to find the suspect inside and called police. And Strange said investigators are prepared for a long night if necessary.
"Time is on our side," he said, adding, "It'd be very difficult for us to go in, but if we have to, we will."
Saturday night's shootings took place at an off-campus apartment complex in Auburn, about 50 miles east of Montgomery. The dead included two former Auburn football players, and a current football player was among the wounded.
Leonard has been the target of an intense manhunt for two days, and two other men have been jailed on charges of hindering prosecution in the case.
Auburn police said one of those arrested, 18-year-old Jeremy Thomas, escaped from the scene of the shootings with Leonard. Montgomery police say 41-year-old Gabriel Thomas tried to mislead investigators during the search, and they arrested him Sunday at the request of U.S. marshals.
Police did not immediately disclose the relationship, if any, between the two men. Both were arrested in Montgomery, but Jeremy Thomas was expected to be transferred to a jail in Lee County, which includes Auburn, police said.
Leonard, a Montgomery resident, had previous arrests for gun offenses, but was never prosecuted, according to media reports. He was still believed to be in the state on Monday, Montgomery Police Chief Kevin Murphy said.
Officers received a call reporting the shooting at the University Heights apartments clubhouse about 10:03 p.m. Saturday, Auburn Police Chief Tommy Dawson told reporters Sunday. Arriving officers found Edward Christian, 20, dead at the scene.
Christian, of Valdosta, Georgia, was off the football team because of an injury, Dawson said. Former player Ladarious Phillips, 20, and Auburn resident Demario Pitts, 20, died later at a hospital, he said. Two others, including current Auburn sophomore offensive lineman Eric Mack, 20, of Cameron, South Carolina, were taken to East Alabama Medical Center in the nearby town of Opelika.
Mack was released from the medical center Sunday morning, while another man, 19-year-old Xavier Moss, was treated and released from the same facility.
A third man, 20-year-old John Robertson, was transferred to the University of Alabama at Birmingham Hospital, where he was in critical condition after being shot in the head.
Leonard and two other men were thought to have fled the scene in a white Chevrolet Caprice, authorities said. Police later found the car abandoned in an adjacent county, Dawson said.
The Opelika-Auburn News reported Monday that a $15,000 reward -- $10,000 from the FBI and $5,000 from the U.S. Marshals Service -- was offered for information leading to Leonard's arrest and conviction.
Court records show that Leonard was charged in 2008 with theft and carrying a pistol without a permit, and in 2009 he was charged with second-degree assault for allegedly shooting a 16-year-old in the groin, according to the newspaper.
However, the cases were not prosecuted. The Opelika-Auburn News reported that a grand jury declined to indict Leonard on the charges. The Montgomery Advertiser reported that prosecutors did not pursue charges against Leonard in the shooting after the victim said Leonard was not the one who shot him.
Leonard also has been involved in two child-support cases, including one filed Friday, The Birmingham News reported. The latest suit claims he is the father of a girl born in 2011. In January, according to the newspaper, a court ruled Leonard was the father of a 4-year-old girl by another woman. He was ordered to pay $305 in child support, $21 of which was to go toward about $7,300 in back child support he owed, the News said.
Police have a motive in the shooting, but Dawson would not release it, saying "that's for the courtroom, later on." He did say authorities believe gunfire erupted during a fight at a party.
Several media outlets cited unidentified witnesses as saying the altercation was over a woman.
Witness Turquorius Vines told affiliate WGCL the violence was sudden.
"It went from us chilling with all these females to a massacre for no reason at all," he said.
"I heard what appeared to be six or seven gunshots outside my apartment," resident Nate Conoly told affiliate ABC 33/40. He said he couldn't see anything when he peered outside his window, but heard screaming. "... I went back into my apartment and locked the door," he said.
A woman identifying herself as only Leonard's grandmother answered the telephone Sunday at an address listed as his in court records, the Montgomery Advertiser reported.
"I'm just very surprised by all of this," she told the newspaper. "This is not the grandson I know, I can tell you that. I've just been sitting here, can't hardly move, I'm so in shock by it. It just doesn't seem real."
Dawson said he was not aware of any connection between Leonard and the university.
Auburn officials expressed condolences to the victims' families, saying many athletes on the football team were grieving after the deaths of Christian and Phillips.
Former Auburn quarterback Barrett Trotter told ABC 33/40 he was "pretty devastated, pretty shocked just like everyone else at what happened."
"When you have that team, family atmosphere we have at Auburn, anything like that is going to be a real blow to everyone there," he said.
Gene Chizik, Auburn's head football coach, called it "a sad, sad day for everyone associated with the entire Auburn family." Chizik said he was "devastated" by the three deaths, including those of Christian and Phillips, whom he knew personally.
"We have a lot of people on our football team that are hurting right now, and we're going to do everything we can to help them get through this," he said. "We are relieved that Eric Mack, who was also a victim in this incident, is expected to make a full recovery. This is a very trying time for everyone involved, and I would just ask that you lift up the victims and their families in your prayers."
"You don't really know what to do after something like this happens," Trotter told ABC 33/40, "but you have to trust the Lord and believe everything is going to be all right."
CNN's Joe Sutton, David Mattingly, Greg Morrison and Ashley Hayes contributed to this report.