The Boston Police Department reports arresting one of two men they say ran from officers investigating a report of men with guns behind the Joseph Lee K-8 School on Talbot Avenue in Dorchester on Monday morning, after the start of the school day.

Officers recovered a Glock 26 with a magazine, loaded with a total of 40 bullets in a bush behind the school, police say.

Police are continuing to investigate whether the gun belonged to Ezequiel Rodriguez, 25, of Dorchester, or the other man, who successfully ran away shortly before 10:30 a.m. - unlike Rodriguez, who police say not only stayed in the area, but returned to the Lee School appearing "to be searching the ground intently while talking on a phone."

Police say officers first arrived at the Lee School after "receiving information that people were outside of the Lee School with firearms."

The officers found three men, one of whom began walking towards them while the other two took off on foot towards Talbot Avenue and then up Bernard - while clutching their waistbands - police say.

A gun-sniffing dog pointed officers to a bush behind the school, where they found the loaded gun, police say.

Rodriguez, meanwhile, returned to the school in his apparent search for something, but police let him go after determining he didn't have a gun on him and there was no way to prove the gun in the bush was his.

But then, police say, officers searching Helen Street, which connects Bernard to Talbot, spotted Rodriguez again, this time leaving a house on Helen with a backpack he had not been wearing in his first two encounters with police:

"Rodriguez was stopped for an investigation that determined he was trespassing and he was placed in custody. A search of Rodriguez’s backpack resulted in the recovery of eight Xanax bars inside a sandwich bag. "

Rodriguez was arrested on charges of trespassing and possession of a class C drug, police say. Dorchester Municipal Court records show he was released on $100 bail at his arraignment on Tuesday.