PORTLAND — After three days of underwater searches, authorities on June 17 suspended efforts to find a missing Scarborough man in Portland harbor.

City Police Lt. James Sweatt announced multi-department search operations for Matthew Foster, 23, had ceased.

“While it is possible that Matthew is in the harbor, we are confident that the area of highest probability has been thoroughly searched,” Sweatt said in a press release.

A dive team searched the waters near Chandlers Wharf for Foster last week. He has been missing since June 10, and was last seen in the Oasis bar on Wharf Street in the Old Port around 11:30 p.m. Foster was expected to meet friends later and never arrived, according to Portland and Scarborough police officers.

“If information is developed indicating a new or specific location, divers will resume their efforts,” Sweatt said. The investigation remains open and we continue to try and re-trace Matthew’s movements.”

There is still no indication why Foster went missing, Sweatt said last week.

Foster, who has Type 1 diabetes, had one daily dose of his medication with him, and was not carrying a cell phone at the time of his disappearance, police previously said. His phone and car are still at his home.

Foster was wearing khakis, a blue button-down shirt and white sneakers. He is 5 feet 11 inches tall and weighs approximately 160 pounds, with blue eyes and brown hair.

As the Old Port becomes increasingly crowded in the summer, Sweatt used the incident to emphasize how important it is that people remember to “act safely” when they’re in the waterfront area, especially at night.

“Stay with your friends, and let other people know where you are and when you’re going to return,” he said.

Sweatt said the department’s thoughts are with Foster’s relatives and friends.

Police said anyone with information should call Scarborough police at 883-6361, or Portland police at 874-8575. Portland Police also accept anonymous tips at 875-8584, online at portland-police.com by clicking “Submit an Anonymous Crime Tip,” or by text at 274637 with the keyword “GOTCHA.

Alex Acquisto can be reached at 781-3661 ext. 106 or aacquisto@theforecaster.net. Follow Alex on Twitter: @AcquistoA.

Staff writer David Harry contributed to this story.