MOORE, Okla. >> A second suburban Oklahoma City high school student has died after a group of cross-country runners was struck by a pickup truck that authorities say was driven by man whose son was killed in a traffic crash over the weekend, a school official said today.

Sophomore Yuridia Martinez, who had been hospitalized in critical condition since the Monday crash, has since died, Dustin Horstkoetter, director of safety and security at Moore Public Schools, said. Officials had previously said that senior Rachel Freeman was killed when the truck slammed into members of the school’s cross-country team.

Moore police Sgt. Jeremy Lewis said authorities believe the students were running on the sidewalk when they were struck. Authorities had previously said they were running along a street outside Moore High School.

Three other students remained hospitalized with injuries. Student Kolby Crum was in critical condition at Oklahoma Children’s Hospital, according to spokeswoman April Sandefer, while students Joseph White and Shiloh Hutchinson were in fair condition. Student Ashton Baza was released Monday night.

The ages of the students have not been released.

School Superintendent Robert Romines praised the reaction of students at the scene of the crash.

“Without hesitation or second thought, our students were there with their friends and began life-saving tactics including CPR,” Romines said.

Freeman was set set to sign a track and field scholarship this week with Ouachita Baptist University in Arkadelphia, Arkansas, Horstkoetter said.

Max Leroy Townsend, 57, was being held in the Cleveland County jail on charges of first-degree manslaughter and six counts of failure to stop and render aid.

Police suspect alcohol was a factor, according to Lewis, who said results from toxicology tests were pending.

“That won’t be for quite a while,” Lewis told The Associated Press. “That’s a blood test that requires being sent to a lab.”

Lewis said Townsend’s son, Cody Townsend, was killed Sunday in a multi-vehicle crash in Moore. But investigators have not yet determined why the pickup crashed into the students on Monday or whether that crash was intentional, Lewis said.

“I know the big question a lot of people have is, ‘Why? What happened? Why did this happen?’” Lewis said.

“I assure you we will find out why and know exactly what happened, and how it happened, and then deal with the individual that caused this after that investigation is complete,” he added.

Max Townsend has a lengthy criminal history in Oklahoma that includes multiple convictions for driving under the influence, public intoxication, possession of drugs and stolen property, stalking and child abuse, court records show. He served time in prison on convictions for child abuse, receiving stolen property and possession of drugs, but was released in 2009, state prison records show.

Moore Police Chief Todd Strickland said different teams are investigating the crash that killed the students and the one that killed Townsend’s son.

Horstkoetter noted that it was not the first time the school system has been hit with tragedy, alluding to a tornado that destroyed an elementary school in 2013, killing seven students.

Romines said 30 mental health specialists were on hand today at the school for students and staff.