A couple from Texas were charged this week in the deadly freeway shooting of a 17-year-old high school girl who was driving to the zoo for a Halloween celebration.

The St. Louis County Prosecuting Attorney’s Office in Missouri charged Willie Herndon, 42, with first-degree murder and armed criminal action in connection with last week’s attack, which killed Alyssa Wilson, authorities said Monday.

Taiya Herndon, who investigators said is his wife, is charged with hindering prosecution, accused of driving her husband to an Illinois hotel 12 miles from St. Louis, prosecuting attorney Melissa Price Smith said at a news conference Monday.

It’s not clear whether either of the two, from Arlington, Texas, has a lawyer. The state public defender’s office for the area did not immediately respond to a request for comment.

The attack killed Alyssa, who was on the precipice of adulthood and optimistic about the journey ahead, her father, Robert Hickman, said at the news conference.

“Alyssa was 17, excited about her life, excited about her future,” he said as he teared up.

The shooting occurred around 7 p.m. Wednesday, when Alyssa was driving south on Interstate 170 in Overland, Missouri, just northwest of St. Louis, said Jack Abell, chief deputy commander of the region’s Major Case Squad. She was on her way to Halloween festivities at the St. Louis Zoo, known as “Boo at the Zoo,” Abell said.

According to security video, Alyssa was traveling south and had just passed a white Buick Enclave that was stopped on the shoulder when the sound of a single round was heard, Abell said at the news conference.

“A person exited the vehicle and stood outside for a short period of time,” he said. “There was a gunshot, got back in the vehicle. The vehicle turned its hazards off and continued on.”

The round went through the rear of the red Buick Encore that Alyssa was driving, Abell said. First responders found Alyssa with a gunshot wound, he said. She was rushed to Barnes-Jewish Hospital in St. Louis, where she was pronounced dead.

The Herndons had no connection to the girl, Abell said.

Wilson was 60 days from turning 18, said Hickman, her father.

“We were getting ready to take our first family vacation together to go to Disney for her to see her favorite person in the world, Princess Tiana,” he said, referring to the character from the animated movie “The Princess and the Frog.”

“Unfortunately, she’s not going to get to do that anymore,” Hickman said. “This was a senseless act.”

The couple were found after investigators used security video of the shooting, as well as automated license plate readers, to track that Buick, which had an out-of-state registration, Abell said.

The vehicle was under surveillance for “long hours” before investigators saw the couple come out of the hotel in Caseyville, where they were taken into custody Friday, he said.

A judge-approved search in Illinois turned up a gun, as well as “supporting evidence,” Abell said, and investigators were analyzing a shell casing found alongside the freeway in Overland.

Major Crimes Unit investigators interviewed Willie Herndon, he said, and came away with a better understanding of the crime.

“During the interview, Willie Herndon provided details regarding his involvement in the incident and additional information pertaining to possible ongoing investigations in other areas,” Abell said. “Those investigations are continuing as we speak.”

The region’s top prosecutor, Price Smith, said charges were filed in Missouri on Friday. Bail in those cases was set at $1 million for Willie Herndon and $500,000 for Taiya Herndon, to be posted in full, the Major Case Squad said in a statement.

The two were being held as prosecutors await extradition to Missouri, authorities said.

Inmate records for the St. Clair County Jail in Illinois show Taiya Herndon is being held on an out-of-state warrant with no bail. The records say she was booked Saturday.

No jail records for Willie Herndon were available.

Alongside 20 or so Major Crimes Unit investigators, the case received help from law enforcement far and wide, authorities said.

“The case was solved within 36 hours due to the collaborative efforts of the FBI, ATF and the many law enforcement agencies that are in this room,” FBI St. Louis Assistant Special Agent in Charge Dave Herr said at Monday’s news conference.

Abell said he could not discuss a possible motive because cases that may be connected to the attack were still under investigation.