A controlled detonation of a suspicious suitcase on Atlantic Avenue in downtown Boston on Friday morning temporarily shut down that section of the city.

Police say 50-year-old James Derepentigny of Lawrence was caught on surveillance video just before 10 a.m. allegedly dropping the suitcase near the rear of a marked Homeland Security vehicle before fleeing down Atlantic Avenue toward High Street.

A controlled detonation of a suspicious suitcase on Atlantic Avenue in downtown Boston Friday morning temporarily shut down that section of the city.

Boston Police Commissioner William Evans said a Homeland Security officer on patrol with a K-9 spotted the unattended suitcase.

Atlantic Avenue was temporarily shut down near Seaport Boulevard, with vehicle and pedestrian traffic diverted from the area. The Interstate 93 northbound ramp at Exit 23 was also temporarily closed.

Police Activity in Boston

As Boston Police descended on the scene and redirected traffic, the FBI was alerted and the explosives unit brought in an X-ray machine to examine the suitcase.

"Inside the suitcase they saw wires and a power source, which drew their attention," Evans said.

Evans added that police do not believe there were explosives in the suitcase. Still, bomb squad technicians deployed what is called a "pack bot" to move the suitcase.

Police were on scene Friday morning after reports of a suspicious backpack were called in.

Marissa Barkey, who works nearby, described the scene.

"This little robot comes out, goes in there, we saw a guy in bomb suits, he comes out and the robot comes out with the actual package and they put it over by that tree and then they detonated it," she said.

A loud detonation that could be seen and heard throughout the area brought back some difficult memories for some witnessing it.

"That's still unsettling for a lot of people, especially we know, with the marathon," said Ricky Caswell, manager of James Hook & Co.

Following the incident, Derepentigny was caught on camera. He was sought until Lawrence Police found him near St Patrick's Church Friday afternoon.

"He was just walking down the street," said Lawrence Police Chief James Fitzpatrick.

Officer Harold Rogers arrested him around 3:30 p.m.

"When you hear 'bomb,' I didn't know if he had any additional weapons on him, or possibly and IED on him himself, so I took him down at gunpoint," said Rogers.

Police say he had no weapons on him, and also had nothing to say about an alleged motive.

"I think his intention was clear, he wanted to create some fear, but nothing related to terrorism," said Evans.

"Certainly putting a lot of fear in people for no apparent reason," said Boston Mayor Marty Walsh.

Lawrence Police say Derepentigny is homeless, but used to live in the area. They say he has eight to 10 arrests in the city involving drug and threat charges.

He is charged with planting a hoax device and is expected to be arraigned in Boston Municipal Court. Additional charges are possible.

Police say Derepentigny was taken down by an officer at gunpoint. He has been arrested at least eight times in Lawrence on charges involving threats and drugs. He has a history of mental health issues, according to investigators.