White supremacist parolee Evan Spencer Ebel, who is believed to have murdered Colorado prison chief Tom Clements and a pizza delivery man after being mistakenly released from prison years early, was able to escape court supervision after his ankle monitor failed in March.

According to ABC News, Ebel, a member of the white supremacist prison gang 211 Crew, was released from prison on Jan. 28 and checked in with corrections officers every day by phone. Police also monitored his ankle bracelet in accordance with parole regulations. 

But when Ebel’s ankle bracelet sent out a “tamper alert” on March 14, he stopped checking in with parole officials as well. While police left messages for Ebel, he failed to return any of them, and officials did not visit his residence in an attempt to track him down until March 19. 

Three days after Ebel’s ankle monitor failed, Denver pizza delivery man Nathan Leon was found dead. On March 19, Ebel allegedly broke into Clements’ home and shot him to death. Police then linked Ebel to both deaths and issued an arrest warrant for him on March 20. 

Ultimately, Ebel fled Colorado and was killed in a shootout with Texas police after a high-speed chase on March 21. Police found the same gun used to kill Clements and Leon in Ebel’s car, as well as pizza delivery equipment believed to belong to Leon.

The revelation that Ebel’s ankle bracelet failed comes only one day after court officials admitted that Ebel was released from prison four years early due to a clerical error. Prison officials mistakenly believed that his two sentences were to be served at the same time rather than consecutively. As a result, Ebel walked free years early. 

It also appears that Ebel’s slaying of Clements may be a small part of a “targeted attack” on prison officials in Colorado and Texas. Kaufman County, Texas, District Attorney Mike McLelland and his wife, Cynthia, were found slain in their home Saturday. 

No suspects have been named in the murders, but the officials are suspected to have been killed by members of the Aryan Brotherhood of Texas, according to CBS News

Ebel’s 211 Crew, also known as the Brotherhood of Aryan Alliance, is not formally connected to the Aryan Brotherhood, which has its hands in criminal activities ranging from drug trafficking to extortion. However, Slate theorizes that due to the close timings and retaliatory nature of the three killings, the white supremacist gangs may in fact be part of a multifaceted attack on prison officials across state lines.