By Nate Raymond

NEW YORK (Reuters) - Two jail guards who have worked at New York City's Rikers Island complex were arrested on Wednesday on federal charges stemming from an assault that led to the death of an inmate there in December 2012.

Brian Coll, a former officer, and Byron Taylor, a suspended guard, were arrested in connection with the death of Ronald Spear, a 52-year-old pre-trial detainee, Manhattan U.S. Attorney Preet Bharara announced.

Prosecutors said Spear died after Coll repeatedly kicked him in the head while being restrained by guards including Taylor.

The men and another guard, Anthony Torres, then tried to cover up the assault, prosecutors said.

Rikers, one of the largest U.S. jail complexes with around 9,800 prisoners daily, has gained notoriety for a culture of violence, including officer attacks on prisoners and several inmate deaths.

Coll, 45, faces five counts including a federal civil rights violation. Taylor, 31, faces three counts including conspiring to obstruct justice.

Following their arrest, a federal judge set bail at $500,000 for Coll, who will be held until conditions are met, and $200,00 for Taylor, who was released Wednesday evening.

Torres, 49, pleaded guilty on Tuesday to two counts, including obstructing justice, and is cooperating with authorities.

Lawyers for Coll and Torres declined comment. Sam Braverman, Taylor's lawyer, said he would "defend him vigorously."

Bharara's office has been among the authorities recently scrutinizing issues involving Rikers.

Norman Seabrook, president of the guards' union, the Correction Officers' Benevolent Association, confirmed last week the union received a grand jury subpoena from Bharara's office seeking financial and other records. A representative declined comment.

In December, Bharara's office joined a lawsuit against the city over violations of teenage inmates' civil rights at Rikers. Bharara said on Wednesday he expects a settlement by June 22 but was "impatient about it."

"Any day that goes by where we don't have enforceable and enduring reform at Rikers Island is one day too many," he said.

A New York City Department of Correction spokeswoman said it was taking steps to ensure its staff "adhere to the highest level of professionalism."

The city agreed last year to pay $2.75 million to settle a lawsuit by Spear's family.

While the Bronx District Attorney's Office investigated Spear's death, it ultimately did not bring charges.

Zoe Salzman, a lawyer for Spear's family, said it was "grateful" for the federal charges.

(Editing by Grant McCool, Leslie Adler and Bernard Orr)