The Middlesex County Juvenile Court in East Cambridge was the scene of an arrest and suspects’ escape Tuesday. (Photo: Google)

A Somerville incident in which shots were fired bled into two neighboring communities Tuesday, with a Medford school sheltering in place briefly as four suspects fled in a car into Cambridge, where two were arrested and two slipped away on foot.

There is no reason to think that the two suspects who escaped are armed or dangerous, said Jeremy Warnick, director of communications and media relations for Cambridge police. The two who are in custody – one a Cambridge teenager, the other a 31-year-old Somerville man – have been charged with receiving a motor vehicle stolen in Boston. “An investigation remains ongoing,” Warnick said. Another person had been arrested earlier in Somerville.

At least two groups of men were involved in a 1:17 p.m. incident in Somerville’s Mystic River Development that involved multiple shots fired and “numerous 911 calls,” though no injuries, Somerville chief of police Charles J. Femino said. The development has 240 units of lower-income housing.

The incident was described by officials as being near Somerville’s Arthur D. Healey School, which teaches kids in prekindergarten through the eighth grade, at Butler Drive and Mystic Avenue. Afterward police issued a “bolo” – an alert for officers to be on the lookout – for the suspects’ vehicle.

The alert was seen by a Medford police officer on break from testifying at the Middlesex County Juvenile Court, 121 Third St., East Cambridge, who then saw a car that fit the description, Warnick said.

The Medford officer took two suspects into custody with the support of the Cambridge and state police, Warnick said, while “two other males in the vehicle escaped on foot.” The identity of the officer was asked of Medford police, who did not immediately respond.

Video of the arrest is here on Twitter.

“After a thorough search by responding officers, they have not been located at this time,” Warnick said of the remaining suspects in a 2:42 p.m. email.

Femino said in a 4 p.m. Tuesday press release that it was a witness at the Mystic Housing Development shooting who provided a description of the car that left the scene, leading to Somerville and state police conducting “an extensive search of the immediate area.” It turned up one firearm and the arrest of one person “who is believed to have been involved in this incident” after being found near the Healy School.

Medford police had said they were “monitoring a situation” near the Healey School that led to the issuing of a 2:05 p.m. shelter-in-place order for the Missituk Elementary School in Medford, about a half-mile from the Somerville incident, according to NBC News in Boston. That order has since been lifted.

“It is not clear whether the individuals [in the Mystic Housing Development shooting] are known to each other. Nor is the motive for the incident determined at this time,” Femino said. “Although we believe there is no ongoing threat to the immediate area, we ask residents to remain alert and report any suspicious activity.”

Shira Laucharoen contributed to this report.