A Washington state teenager suddenly disappeared on a late night boat trip with his friends after telling them he needed to use the restroom.
The Mercer Island Police Department said that the 19-year-old was believed to have fallen into Lake Washington, near Seattle, on Friday night around 10.40pm.
His identity has not been disclosed at the request of his family, the Seattle Times reported.
The teen was on the lake to watch the much-acclaimed annual Seafair air show and hydroplane races, which began around noon that day.
As the group's vessel prepared to leave the log boom area between Seattle and Mercer Island, the teen 'reportedly told others on board that he needed to use the restroom,' according to police.
The boat was already moving at the time and may have been traveling at planning speed, law enforcement added.
Once the group reached the east high-rise portion of the Interstate 90 floating bridge and had to slow down because of speed restrictions, they realized the 19-year-old was missing.
They searched on their own for roughly five minutes before making a call to 911.
A 19-year-old is missing after he is believed to have fallen off a recreational vessel into Lake Washington on Friday night around 10.40pm
Mercer Island authorities have warned that Lake Washington 'can be overwhelming' during Seafair weekend because of the massive boat traffic (Previous photo of the lake)
The Seattle Fire Department said Seafair security had reported hearing someone calling for help from the water around Stan Sayres Park, according to KING5.
That happened before a massive search for the teenager began, which included officers from the Mercer Island Police Marine Patrol, as well as help from the US Coast Guard, Seattle Police Harbor Patrol and others.
Authorities used infrared technology, spotlights and thermal-imaging drones to look for the missing teen.
The current search area is roughly 10 square miles and includes the waters surrounding the Lacey V. Murrow Memorial Bridge, according to police.
Mercer Island acting police chief Jeff Magnan said the 'time period and even the location [was] pretty vague' when it came to the disappearance.
'We are looking at a pretty big swath of lake,' Magnan told KIRO7.
He said that law enforcement was still holding out hope, even though updates had been scarce.
'We are hoping he made it to another boat or made it to the shore and everything is going to be fine,' Magnan said.
'But we have not heard anything from him or his family that he has been located,' he added.
The search area for the missing teenager is approximately 10 square miles and includes water surrounding the Lacey V. Murrow Memorial Bridge (pictured), per Mercer Island police
Seafair is an annual occasion in Seattle where boaters watch hydroplane races and air shows put on by the US Navy Blue Angels
Magnan said that he did not expect many witnesses besides the group that was on the boat.
They have already talked with investigators in regards to the teen's disappearance, according to the acting police chief.
Magnan said the next step was to obtain and analyze cell phone records in order to retrace the path the vessel took.
Mercer Island police said the search had been suspended on Saturday at around 12.30am because of 'darkness and operational considerations.'
Authorities resumed the effort during the day but still did not locate the missing teenager.
The search was later called off again due to Federal Aviation Administration restrictions related to Seafair, which happens every year in Seattle and is headlined by an air show courtesy of the US Navy Blue Angels.
Magnan advised boaters to be particularly careful during Seafair weekend, when Lake Washington becomes so cramped that it 'can be overwhelming.'
'The lake is a lot busier than it normally is,' he said. 'There's always a stockpile of new boaters who have never experienced this.'
The Daily Mail reached out to the Mercer Island Police Department for comment.
