Image copyright Reuters Image caption Hernandez said he was very happy after the acquittal

Former US footballer Aaron Hernandez has been acquitted of a drive-by double murder that prosecutors said began over an argument about a spilled drink.

On Friday he was acquitted of seven charges, but was found guilty of illegally possessing a firearm.

The former tight end for the New England Patriots is already serving a life sentence for killing a man who was dating his fiancee's sister.

Hernandez cried in court as the verdict was read, saying he is "very happy".

A judge added five years to Hernandez sentence after the verdicts were read.

He had been accused of the fatal shooting of Daniel de Abreu and Safiro Furtado outside a Boston nightclub in 2012.

Prosecutors said it happened after the American football star became enraged that one of the men had bumped into him causing him to spill his drink.

Lawyers for the state relied heavily on a former friend of Hernandez, Alexander Bradley, who said he had been the driver for the shooting.

Bradley, who is serving a prison sentence in another state, was granted immunity in order to testify.

He had also claimed that Hernandez shot him in the face, causing him to lose sight in his right eye, after becoming paranoid that he would tell someone about their crime.

Hernandez's lawyers mocked the immunity agreement as the "deal of the century".

One month after the deaths, Hernandez signed a $40m (£32m) extension contract with the Patriots.

Prosecutors pointed to one of Hernandez tattoos as evidence that he had committed the attack.

"That is not random. That is not art. That is evidence," Patrick Haggan told the court about a depiction of a handgun beside five bullets - the same number fired in 2012.

"That is a confession."