UPDATE 7:45 P.M: The 17-year-old arrested in connection with the shooting allegedly when the shooting happened, according to the Middlesex District Attorney's Office.

UPDATE 1:30 P.M.: Matt Byrne of the Boston Globe reports witnesses told him the suspect opened fire on the teenage victim and nonchalantly walked away: John Stelmach, 38, of Malden, a driver for Malden Taxi, said "I saw the whole thing, said Stelmach, who was standing in the doorway of Malden Taxi at 290 Eastern Ave. "I was watching traffic, and I saw a group of kids. I saw one kid who was standing on the sidewalk pull out a gun and just start shooting.

Stelmach said the target was a young man riding a bicycle through the parking lot of a restaurant on Eastern Avenue. "After the kid the four or five shots, he turned around and started walking nonchalantly down Eastern Avenue. It was crazy."

Nancy Kjersgard, 46, of Wakefield, said she was driving on Eastern Avenue when she looked into the parking lot of the Sun Kong restaurant at 275 Eastern Ave. and saw a group of teenagers on the corner and another riding a bike. "I saw the kid go down," she said. "Then the kid who shot him started walking away like it was nothing." UPDATE 1:25 P.M.: WCVB-TV is reporting that the victim was a teenager and riding a bike when he was shot around 10:30 a.m. this morning.

UPDATE 12:12 P.M.: Malden Police have arrested a suspect allegedly involved in the shooting and secured the crime scene, according to an emailed statement from Mayor Gary Christenson's office.

"The condition of the victim is unknown at this time," the statement said.

Malden Schools Superintendent David DeRuosi, Jr. told Malden Patch that schools were placed on temporary lockdown, given the timing of the shooting close to lunch and recess and time. "I made a decision to play it safe," DeRuosi said shortly after noon. "We got cleareance from the police, which we have just recently received. It was purely 100 percent precautionary."