The grieving uncle of a 17-year old Bethesda youth has written to the Montgomery County Council demanding the investigation be referred to an outside law enforcement agency. Navid Sepehri died after apparently drowning in a stream 19 hours after an encounter with police at a suspected underage drinking party this past weekend.

"This is the time to call the FBI because family cannot trust this police department anymore,” wrote Jamshid Sepehri, uncle of Navid, who was a senior at Walt Whitman High School. Navid's body was found by his father near the Bannockburn Swim Club late Sunday.

Navid had a bottle of vodka in his pocket, his father said.

RELATED: Father demands answers after teen dies following underage drinking party

The Sepehri family said police could have prevented the tragedy during an encounter captured on officers' body camera video with Navid Saturday night. Officers had been called to break up a suspected underage drinking party when they met the teen, who was apparently "under the influence", according to police.

The family also accused police of a lackluster response once it was apparent the teen was missing.

In his letter to the county council, Jamshid Sepehri wrote:

“... your cops did not even bother to make a report when my brother asked them to help him find his son at 3 am. They did not bother to inform him about the party and your officers' interaction with my nephew and the fact that he was drunk. Had they given him that information at that hour he would have called the family and friends to go do the search because your cops could not be bothered with that kind of task. “

RELATED: Police encounter Bethesda teen at alleged underage drinking party before his death

Mr. Sepehri came to the police department’s 2nd District station at 3:23 a.m. Sunday, but did not take a report from him, according to a statement from Montgomery County Police.

“A report should have been made,” said police spokesman Capt. Paul Starks Wednesday.

A formal missing person report was finally taken at 12:46 p.m. Sunday, according to police.

Starks explained that officers did not arrest Navid Sepehri during the encounter outside the party because he was not in violation of any law, despite being apparently under the influence.

“The law prohibits us from taking him into custody because he was not in possession of an alcoholic beverage at the time we had contact with him,” Starks said.

According a written police statement: “The juveniles explained to officers that they were now waiting for their parents to come and pick them up. Officers recognized that Sepehri may have been under the influence and confirmed with the juveniles that Sepehri would leave when the juveniles left. Officers determined that there were no applicable criminal or civil charges to be placed against the juveniles they had encountered and the officers then went to speak with the adults of the home.”

When asked if the actions of officers would be reviewed, Starks said, “This case remains an active investigation.”

Police had been called to the home in the 6500 block of Elgin Dr. at about 10:30 Saturday night for a report of a suspected underage drinking party with a bonfire, according to recordings of the police radio dispatch.

According to the police statement, adult residents of the home told officers that older teens came to the party uninvited with alcohol and as a result everyone had been told to call their parents for rides home and to leave.

Police did not “observe any evidence of an ongoing party,” according to the department’s written account.

No citations were issued to any juveniles or adults.

RELATED: Eyewitnesses claim teen was at underage drinking party before death

In his letter to the county Council, Jamshid Sepehri demanded an investigation into who may have sold or given Navid alcohol before he died.

“Just like guns, alcohol and drugs are also weapons that kill people just the way my nephew was murdered,” wrote Jamshid Sepehri.