FREDERICK, Md. — Metropolitan Police suspect the Salvadoran gang MS-13 may have been involved in the disappearance of a 16-year-old boy from Frederick, Maryland, according to sources with knowledge of the investigation.

Detectives are all but certain a mutilated body found beneath Chain Bridge in D.C. Saturday is Eberson Guerra Sanchez, a ninth grader who went to Tuscarora High School in Frederick.

Final confirmation from the D.C. medical examiner is pending.

The body showed signs of being badly beaten and possibly hacked with a machete. One hand was severed and the other was barely attached, sources close to the investigation said.

Thursday, in a letter to the school community from Principal Christopher Berry, school officials announced Sanchez’s death.

“The Washington D.C. and Frederick City police continue to investigate the circumstances of his death,” Berry wrote. “We have no reason at this time to believe the circumstances are connected to Tuscarora High School or other students who attend here.”

One of Sanchez’s family member reported him missing to the Frederick City police late Friday, April 26, according to Lt. Kirk Henneberry. The boy had last been seen around 6 p.m. that day.

The body believed to be Sanchez was discovered by fishermen the next day in a wooded area of the District between the C and O canal, and the banks of the Potomac River near Chain Bridge.

The area had been marked by blue and white bags which might suggest MS-13 involvement because the colors are used by the gang, according to police sources.

RELATED: 9th grade Maryland student found dead in DC