Updated

A federal judge ruled Thursday that Michael Slager, the former South Carolina police officer who fatally shot an unarmed black man, committed second-degree murder.

He was sentenced to 20 years in jail without a fine. Slager will also receive mental health counseling until he is released from prison.

The ruling comes after Slager, 36, pleaded guilty in May to violating Walter Scott’s civil rights. He had said he shot Scott multiple times in self-defense, alleging Scott had attempted to grab his Taser. Cell phone video captured at the scene, however, showed Slager shooting Scott in the back as Scott tried to run away.

Federal officials recommended 10 to 13 years in prison, but Slager's attorneys argued he should face far less time.

Slager first began his sentencing hearing Monday. In light of the ruling, here's what you need to know about Slager's case.

What did Michael Slager do?

Slager, a white police officer in North Charleston, S.C., encountered Scott on April 4, 2015, after he stopped him for a non-functioning taillight.

USA-SOUTH CAROLINA/SHOOTING

A bystander took cell phone video of Michael Slager shooting Walter Scott eight times as he ran away. (Reuters/Feidin Santana)

The altercation between Slager and Scott has been heavily debated and scrutinized, according to the Charleston Post and Courier. Prosecutors alleged that during a struggle between the two men on the ground, Slager remained in control of his Taser. They said he threw the device to the ground at one point in order to grab his firearm.

Cell phone video taken by a bystander showed Scott attempting to run away after the stop. Slager then fired his gun eight times at the fleeing man, hitting him five times.

After he shot Scott, Slager dropped the Taser near Scott's unmoving body, according to the Post and Courier. Later, as seen in the video, Slager picked up the Taser and returned it to his belt, the newspaper reported.

Slager argued that he fired his weapon as self-defense, even as Scott ran away. His attorneys had also argued that the use of force “was … rooted in Scott’s misconduct,” according to the Post and Courier.

The Scott family previously reached a $6.5 million settlement with the city of North Charleston.

What already happened in court?

A grand jury indicted Slager in 2015, but a judge ultimately declared a mistrial in December 2016 after a jury remained deadlocked. The panel was made up of 11 white jurors and one black juror.

While that case was ongoing, federal authorities pursued a parallel investigation against Slager on civil rights charges. Solicitor Scarlett Wilson had planned to bring a second case against Slager later this year, but those charges were dropped as part of his federal plea deal.

Slager pleaded guilty in May to violating Scott’s civil rights.

A probation officer recommended a prison term between 10 and nearly 13 years, the Post and Courier reported.

He was sentenced Thursday to 20 years in prison with no fine.

Fox News' Kaitlyn Schallhorn, Madeline Farber and Terace Garnier contributed to this report. The Associated Press also contributed to this report.