Update, 7 p.m.:
Update, 1:15 p.m.:
Massachusetts State Police had been called to the area to search for a suicidal person, according to Mike Moura, @NEFirebuff, on Twitter.
After about a 25-minute search for a missing person, a female body was found in at about 12:35 p.m., according to police scanner reports.
The female was dead on arrival, according to the reports.
A helicopter was seen above the park at about the same time.
Stay tuned to Arlington Patch for updates as they become available.