Former Chicago police officer Jason Van Dyke was released from prison on Thursday after serving less than half of his nearly seven-year prison sentence for the murder of Black teen Laquan McDonald.

A jury convicted Van Dyke in 2018 of second-degree murder and 16 counts of aggravated battery ― one for each bullet the white officer shot at the 17-year-old on a Chicago street in 2014. He was sentenced to 81 months, which meant that he could be released in about half that time with good behavior.

“The punishment that he received … does not match the criminal act that he committed on Oct. 20, 2014, and furthermore, there’s individuals in Cook County Jail that are spending more time in detention waiting to go to trial than what Jason Van Dyke has spent in the Illinois State Penitentiary,” said community activist William Calloway, according to WTTW-TV. Calloway was central in pushing for the city to release the footage of McDonald’s death, and he is leading the charge in calling for federal charges against Van Dyke.

Illinois law states that judges can sentence people only for the most serious crime they’re convicted of when they’re found guilty of multiple crimes for a single act. Prosecutors tried to make the case for sentencing Van Dyke on the aggravated battery conviction, which carries a minimum sentence of six to 30 years in prison for each count.

Cook County Judge Vincent Gaughan decided to instead sentence him on the second-degree murder charge, which carries a maximum sentence of 20 years, because he ruled that was the more serious crime. The decision led Illinois Attorney General Kwame Raoul and special prosecutor Joseph McMahon to appeal Van Dyke’s sentence to the Illinois Supreme Court. However, the court ruled that the former officer’s sentence stood.

A growing number of voices, from activists to officials, are calling for John Lausch, the U.S. attorney for the Northern District of Illinois, to bring federal charges against Van Dyke. Rep. Bobby Rush (D-Ill.) said last week that Van Dyke should face federal civil rights charges, and Sen. Tammy Duckworth (D-Ill.) voiced her support on Monday for the Justice Department to conduct a civil rights investigation into McDonald’s death.