OAKLAND — A man swimming in Lake Merritt on Tuesday morning drew a crowd of onlookers, and police and fire crews along the shore.

The man was pulling a suitcase along as he swam, sometimes doing the backstroke, and holding a plastic bottle of water. He finally got out of the lake about 11:20 a.m. and was detained in 2000 block of Lakeshore Avenue.

While rowers, sail boaters and gondoliers use the man-made lake regularly, swimming is prohibited.

That has not stopped people from using the lake as a dump, as over the years voluteers have pulled scores of items from its murky waters, including ski boots, underwear, toys, drug paraphernalia, chairs, cell phones, cigarette butts and even an ankle monitor that someone on bail, probation or parole might wear.

Police initially received a report at 10:55 a.m. that a person was drowning in the lake. Officers located the man swimming in a part of the lake near Bellevue Avenue and used a bullhorn to ask him to swim to shore.

The 40-year-old man, who told police he was from Washington state, offered no resistance to officers and was detained for a psychiatric evaluation.

“The officers did a good job with the situation and made sure he got the treatment he needed,” Oakland police spokeswoman Johnna Watson said.

Some onlookers that regularly walk around the lake remarked that they had never seen anyone swimming there before.