A man on probation for a 2014 guilty plea in a drug case was identified by police Tuesday as the man they are seeking in the fatal shooting of 29-year-old John Le in Havertown on Saturday, a random killing in a quiet suburban neighborhood that police said followed a shooting spree by the same man in Philadelphia's Overbrook Park section.

Derrick Hershal Rollins, 24, remained at large Wednesday morning.  Havertown Township Police Chief John Viola said Wednesday that police were "still out there looking for him" but had no new leads.

Lt. John Walker of Southwest Detectives said at a news conference Tuesday afternoon that Rollins probably was in the city, and that investigators had searched houses in West Philadelphia and Kensington looking for him.

Detectives also still were searching for the gun used in the killing, Walker said. Shell casings from the Haverford Township slaying matched those recovered from the shooting in Overbrook Park, he said, bolstering the theory that Rollins had pulled the trigger in both incidents.

Still, one thing remained a mystery as police in at least two counties tried to find Rollins: a motive for his alleged crimes. Rollins did not know Le, apparently didn't steal anything from him, and didn't know the people at whom he allegedly fired 17 shots in Philadelphia about 45 minutes before attacking Le, according to police.

"This guy is a dangerous individual," Walker said. "We need him off the streets."

Court records show that Philadelphia police arrested Rollins in February 2014 and charged him with possession of drugs with intent to deliver. That May, he entered a guilty plea and was sentenced to five years' probation, the records show.

Court records also show that Rollins was arrested July 24, 2014, on firearms charges. Common Pleas Court Judge Giovanni O. Campbell dismissed those charges with prejudice in November 2016 because one arresting officer was sick and another was on vacation, the records show.

Philadelphia police described Rollins as black, 6 feet tall, thin build, about 160 pounds, with a dark complexion, a full close-cropped beard and mustache; last seen wearing a thin, red pullover sweatshirt and gray jeans.

Delaware County District Attorney John J. Whelan said search warrants had been issued for a residence connected to Rollins, and for his gray Volvo sedan. Police recovered the car early Tuesday in a parking spot on the 5100 block of Locust Street in West Philadelphia, the block where police believe he has been living. Police were "working aggressively" to find and arrest him, Whelan said.

Haverford Township Police Chief John Viola also said that "there are some significant leads" in the investigation, and that detectives were running down tips.

Police homed in on the 2004 Volvo S60, which Rollins owns, in part because of a tip from someone who reported seeing it being driven at high speeds Saturday and gave police the first three numbers of the license plate, authorities said Tuesday. Police believe Rollins drove the vehicle from the scene of the first shooting — on 77th Street in Philadelphia — into Haverford Township, then used it as a getaway car after the murder.

The vehicle was taken to a Philadelphia police impoundment lot in North Philadelphia for processing, Walker said.

On Tuesday morning, police with a warrant also raided a white and blue house at 5128 Locust St. Evidence of a raid could be seen in dents in the front door, splintered wood around the lock, and a rattled woman who gave her name as Nannette.

"Hell to the no!" she said when asked if the shooting suspect had been living at her home. The man — whom she said she knew only as Derrick — has known her granddaughter for seven years, had been dating her for about six months, and had visited the house from time to time, she said. The visits were always in the basement, Nannette said.

"I don't know him, didn't see him. He was going with my granddaughter, as far as I know," Nannette said, standing behind her partially opened front door. "I never even heard his last name. She would just say, 'Derrick.' … They found each other for the last six months. She'd say, 'I seen Derrick today.' I'd say, 'That's nice.' "

Nannette said she and her husband, a retired police officer, have lived in the house for 30 years. "I hope they catch him," she said. "There's no shame in my game.  I'm just shocked."

William McDonald, 61, who said he has lived his entire life on the 5000 block of Locust — a block from Nannette's house — said police Tuesday morning also raided an apartment building at 51st and Locust. Shown newspaper photos of the shooting suspect released by police, McDonald said he last saw the man on the block about four days ago wearing the same red hoodie.

On Facebook, Rollins is known as Derrick Twit Rollins. His page says that he hails from Belfield, N.D., and graduated from Audenried High School in 2009 and Slippery Rock University in 2013. Officials at the university in Butler County said Tuesday they had no record that Rollins was ever enrolled there.

Le was a graduate of Lower Merion High School and Temple University. Friends described him as gentle and optimistic, with an affinity for disc golf and tennis. Police said he lived with his parents in Narberth, and tributes poured in to a fundraising website set up by friends this week.

Less than an hour before Le was shot, police said, Rollins fired 17 shots at two people who drove up to confront him. Walker said the two believed Rollins was acting suspiciously. They managed to drive away without getting hit, though he chased them in his Volvo before they lost him, Walker said.

Then, just after 6 p.m. on the 2300 block of Haverford Road, Le was shot in the torso as he tried to enter a friend's apartment after stopping at a pizzeria, police said. Police said he had been scheduled to play a tennis match that was canceled due to weather.

Authorities on Saturday released photos of a man in a red hoodie, and police said the images generated tips that helped them narrow their search.

A $5,000 reward is being offered for information that leads to an arrest and conviction. Tipsters can call 610-565-6500.

Staff writer Adia H. Robinson contributed to this article.