Colorado 20th Judicial District Attorney Michael Dougherty has indicted nine parents and others who allegedly allowed underage drinking to occur before a fatal crash on the night of a high school prom in April.

On April 9 following an after-prom party, a 17-year-old girl allegedly got into a truck to pick up more alcohol and ended up driving on the wrong side of the highway, killing herself and two people and injuring one other victim, according to Dougherty's office.

After a grand jury investigation, the district attorney's office returned nine indictments to five parents, a party bus driver, a liquor store and two companies.

The indictments allege that the "two companies sold fake identifications to numerous high school students, a liquor store regularly sold alcohol to underaged persons, the driver of a party bus allowed students to drink on the party bus, and several adults aided and facilitated in underaged drinking on that night and on prior occasions," a press release states.

COLORADO NATIONAL MONUMENT CRASH LEAVES 1 DEAD, ANOTHER INJURED

"Furthermore, it is alleged that the adults did not supervise these underaged persons or seek to prevent them from later driving under the influence of alcohol," the press release states.

GRAND CANYON NATIONAL PARK MOTORBOAT INCIDENT ON COLORADO RIVER LEAVES 1 DEAD, MULTIPLE INJURED

Many witnesses refused to testify, according to the DA's office, and the grand jury submitted subpoenas for witnesses to testify about the events leading up to the crash that killed the 17-year-old, as well as rideshare driver Ori Tsioni and passenger Gregoria Morales Ramirez on Highway 157.

Another victim, Diana Spencer, sustained multiple rib fractures as a result of the crash.

"I want to thank Boulder Valley School District for their cooperation and the investigators for their hard work in this tragic case," Dougherty said in a statement earlier this month.

The Colorado State Patrol, Liquor Enforcement Division and the DA's office were all involved in the joint investigation.