WATERVILLE — Police on Friday released a security camera photograph of the man who robbed the TD Bank on Main Street on Thursday evening.

The robber, apparently acting alone, held up the bank at about 5:50 p.m., handing a note to a teller that police said included “a threat of violence.”

“We are actively investigating the case, but are not able to comment on what, specifically, we are doing in our efforts to identify and locate the person or persons responsible,” Deputy Police Chief Charles Rumsey said in a news release Friday. “If we have additional information that we are able to release, we’ll do that when the time comes.”

The teller handed over an undisclosed amount of cash and the robber left the bank on foot on Main Street toward Appleton Street.

The robber was described as a man about 6 feet tall, weighing about 250 pounds, wearing a dark jacket, a black face mask and baseball cap and gloves.

About 10 police cruisers went to the bank in response to the robbery report. A state police dog team was not able to pick up the robber’s trail.

Police wouldn’t release the amount of money taken in the robbery or identify the nature of the threat made against the teller.

It was the first bank robbery in Waterville in nearly a year. The last robbery, on Feb. 28, 2014, was at the Bangor Savings Bank branch on upper Main Street, in which the robber escaped with about $3,700 in cash. David Alvarez, of Thomaston, was arrested about two hours later after a city police officer recognized him in surveillance tape. Alvarez pleaded guilty in June and is serving a five-year prison term.

Last week, on Feb. 6, a manager was robbed at night by a masked man outside Rent-A-Center at 180 Elm Plaza off Main Street. Police are still investigating that case. The robber was described as being about 6 feet 2 inches tall and was wearing a black and red hunting jacket.