Man tied to 2 deaths kills self aboard bus

A 20-year-old Canadian man described as ''a person of interest" in two killings yesterday in Maine fatally shot himself in the head in front of stunned passengers on a bus in Boston last evening as police closed in, authorities said.

Maine State Police spokesman Stephen McCausland confirmed that the person who shot himself was Stephen A. Marshall, of Cape Breton, Nova Scotia. Marshall had been sought in two homicides of registered sex offenders early yesterday in Maine, one in Milo and the other in Corinth.

''We were seeking Marshall as a person of interest in this," McCausland said. It was not clear last night why Marshall allegedly targeted the victims.

David Procopio, spokesman for the Suffolk district attorney, said in an e-mail last night that Marshall shot himself with a .45 caliber handgun on a Vermont Bus Lines vehicle. Authorities recovered that weapon, and emergency personnel found a second gun on Marshall, Procopio said.

Marshall died at Boston Medical Center last night, hospital spokesman Jim Kennedy said. Marshall would have faced firearms charges in Suffolk County and murder charges in Maine, Procopio said.

No one else was shot, but five passengers were medically evaluated after being hit by blood spatter, Procopio said.

An MBTA police officer at the scene said police received a tip that a murder suspect was on board a bus bound for South Station from Bangor, Maine.

About 8:15 p.m., T police stopped the bus on the ramp several hundred yards from the South Station bus terminal; the man is believed to have shot himself in the head when he saw police.

MBTA spokesman Joe Pesaturo said transit police had stopped the bus at the top of the ramp and asked the driver to turn the lights on inside the vehicle.

''It was shortly after the lights in the bus were turned on that the individual turned the gun on himself," Pesaturo said.

Passenger Zhaohua Dai of Canada, interviewed as he emerged from questioning last night at MBTA police headquarters, said he was seated behind the driver when he heard the gun fire. He said a woman sitting closest to Marshall was spattered with blood.

Dennis Raven, 18, of Brockton, said he was at South Station to pick up his cousin, a passenger on the bus, coming from Maine. ''All he told me was that some guy was shot on the bus."

He said his cousin was 3 feet away from the man, who he said was shot in the head.

Most passengers were taken by bus to MBTA police headquarters so that their statements could be taken. The bus depot, which is controlled by the MBTA, was closed for a period after the shooting, but no train schedules were affected, Pesaturo said.

Maine State Police had issued an alert early yesterday for Marshall after the victims were found shot to death at their homes in the towns northwest of Bangor.

Police identified the shooting victims in Maine as Joseph L. Gray, 57, of Milo and William Elliott, 24, of Corinth. Marshall had gone to Houlton, on the Canadian border, for the first time to meet his father, McCausland said.

Both shooting victims were registered sex offenders, State Police said, and as a precaution yesterday, authorities took offline the Maine Sex Offender Registry, which is maintained by State Police and contains the photos, names, and addresses of more than 2,200 Maine registered sex offenders.

Earlier, police throughout the state were notified to be on the lookout for a small white pickup truck with a lone man inside who was seen leaving the shooting scene in Corinth at about 8:15 a.m., about five hours after the first shooting in Milo was reported. The truck subsequently was found near the Sawyer ice arena in Bangor. State Police said there was no sign of the driver.

Bullets were found in a Bangor bus terminal and reported to Maine State Police, who suspected the bullets might match a gun Marshall had available to him, McCausland said.

Someone matching his description had been seen earlier boarding a bus headed from Bangor to Boston, and Maine State Police alerted Boston police.

At MBTA police headquarters last night, Lieutenant Detective Mark Gillespie praised the MBTA police decision to stop the bus when they did. He said police ''made a very good decision preventing the bus from entering the terminal, where there were thousands of holiday travelers."

Globe correspondent Sean M. Greene contributed to this report. Ralph Ranalli can be reached at ranalli@globe.com. Material from the Associated Press was used.