NEW YORK (AFP) - A US jury on Tuesday returned a second conviction over the 2013 Boston Marathon attacks, finding a friend of the prime suspect guilty of lying to investigators.

Robel Phillipos, 21, was convicted on two counts of making false statements to authorities after the twin bombings, which killed three people, a spokeswoman for federal prosecutors told AFP.

He faces up to 16 years in prison.

Sentencing is set for Jan 29.

Phillipos is the second university friend of Dzhokhar Tsarnaev, who stands accused of carrying out the attacks with his brother Tamerlan, to be convicted at trial.

Azamat Tazhayakov was convicted in July of obstructing the investigation and of conspiracy over disposing of a backpack belonging to Tsarnaev after realising his friend was a suspect.

A third friend, Dias Kadyrbayev, 20, pleaded guilty in August to removing evidence - the backpack and a laptop - from Tsarnaev's dorm room.

Twin bombs planted at the marathon finish line killed three people and injured 264 in the northeastern city on April 15, 2013.

Tsarnaev is due to stand trial in January. He is accused of 30 federal charges and could face the death penalty if convicted.

His older brother Tamerlan was killed in a shootout with police in the days after the attacks.