Florida cops on Tuesday busted a former St. John’s basketball player suspected of being the serial killer linked to four murders in one Tampa neighborhood, officials said.

A tip about a gun at a McDonald’s led to the arrest of 24-year-old Howell Emanuel “Trai” Donaldson III, police announced.

Donaldson had a brief stint as a walk-on player in the 2011-12 season for the Red Storm, school sources said. The point guard from Alonso High School in Tampa never played in any games.

A LinkedIn page apparently belonging to Donaldson said he graduated from the Queens University in 2015 with a degree in sports management.

The profile also said he worked for the Mets in the 2016 season as a “guest experience host,” scanning tickets for season subscribers and VIPs and operating elevators.

He’s suspected of killing four people in the Seminole Heights neighborhood since Oct. 9.

He was busted at a Tampa McDonald’s where he was employed after he walked in Tuesday and handed the manager a 9mm handgun. He asked his boss to hold on to it for him, employee Gail Rogers told the Tampa Bay Times.

While Donaldson walked away to apply for a payday loan at a nearby check-cashing store, Rogers said, the manager alerted a policewoman in the restaurant.

The cop called for backup and officers took Donaldson in for questioning when he returned. It was not revealed how he was linked to the killings.

The four random murders didn’t appear to be robberies, leading police to believe they were the work of a serial killer.

Tampa Police Chief Brian Dugan made the announcement of an arrest, but was short on details.

“Unfortunately, I will not have the answers that you want,” Dugan said. “This is an ongoing situation.”

Mayor Bob Buckhorn said he’s glad the manhunt appears to be over.

“Fifty-one days ago, I said this was a struggle between good and evil,” he said. “Well, tonight goodness has won.”