BRENTWOOD — A Massachusetts man was sentenced to 12 months in jail Friday for tossing a loaded handgun into the woods while leading Salem police officers on a foot chase.

Byron Calderon, 20, of Haverhill, Mass., pleaded guilty to five charges in Rockingham County Superior Court as part of a plea deal with prosecutors.

Police had pulled over Calderon on May 24 for a traffic violation as he was driving a 2000 Honda Accord along Pelham Road near Exit 2. Calderon stepped out of his car, as instructed by police, but then jumped over a guard rail and ran into the woods.

Several plain clothes detectives who happened to be in the area joined in the foot pursuit and apprehended Calderon a short time later. One officer found the loaded firearm under some leaves, after seeing Calderon throw something when he stepped out of the vehicle, police said. Police who pulled over Calderon had noticed several bags of marijuana inside the car, sitting in plain sight.

Calderon was sentenced to 12 months Friday for a felony count of falsifying physical evidence for tossing the gun. He was also sentenced to charges of possession of a controlled drug with intent to sell, control of a vehicle where a drug is kept, resisting arrest and carrying a firearm without a license.

Assistant County Attorney Ben Leduc said that Calderon only had one prior conviction, in 2007 for shoplifting in Salem.

Judge Marguerite Wageling quizzed Calderon about giving up his right to go to trial before accepting his guilty pleas. Had Calderon been convicted at trial, he could have faced up to 3½ to 7 years on the falsifying physical evidence charge and a similar sentence on the drug charge.

Calderon will remain on probation for two years, and will be required to tour the state prison.