SOMERVILLE, MA — The reward for information leading to the arrest of a bank robbery suspect accused of shooting at Somerville police has doubled, according to the FBI. Authorities are offering $20,000 as the man remains on the run more than a week after the robbery.

The suspect is described as a 20-35-year-old Hispanic man standing 5 feet 10 inches, with a medium to heavy build. He was wearing a black stocking hat, camouflage jacket, blue jeans and black sneakers.

Police said he exchanged gunfire with officers during a robbery at Middlesex Federal Savings Bank just before 10 a.m. on May 1. No one was hit, and the suspect ran from the scene, according to police.

The FBI released surveillance video last week of the suspect inside the Davis Square bank. Footage from a nearby business showed a bystander, Dave Powers, knocking the suspect into a shrub as he fled on foot. Powers's quick thinking caused the suspect to lose his backpack, which had money and a gun inside. Watch this video to help @FBIBoston @SomervillePD identify this suspect wanted in connection with an armed bank robbery in Somerville, MA. We're offering a reward up to $10K. Call 857-386-2000 or email https://t.co/48YS0b0hkh https://t.co/1o5LapHvUQ

— FBI Boston (@FBIBoston) May 2, 2019 Here is surveillance video of the man wanted for robbing a bank in Somerville, then firing his gun several times including once at an officer. Two angles here. pic.twitter.com/j5QHmv8dmU

— Jonathan Hall (@JHall7news) May 1, 2019 Powers told WHDH he saw the man was being chased by a police officer and knew he was "in a position to react."

Somerville Mayor Joseph Curtatone said the suspect is "dangerous" and has "no regard for human life." Roads and public transportation were shut down May 1 as officers searched nearby homes and a police helicopter canvassed the area, according to social media reports. Residents and students were urged to use caution, stay indoors and report any suspicious activity to police.

A person of interest was detained, but officials said they're "confident now it was not the person," according to NBC Boston. Authorities believe the suspect is no longer in the area, the network reported.

Anyone who can identify the suspect is asked to contact police at 617-625-1600 ext. 7220 (during business hours) or ext. 7254 (24/7). Tips may be left anonymously through text. Begin your text message with 617spd and send it to TIP411 (847411).