Three young siblings, including a 13-month-old boy, were killed Sunday when the car they were riding in was struck from behind by a speeding pickup truck driven by a man who investigators suspect was intoxicated, Prince George’s County police said. The two other youngsters who died, a boy and a girl, were 5-year-old twins.

“I am heartbroken over the loss of these three young innocent lives,” Police Chief Hank Stawin­ski said of the crash, which occurred about 9:40 p.m. on Indian Head Highway near Wilson Bridge Drive in the Oxon Hill area.

Police said the impact of the pickup against the rear of the car was so forceful that the car’s roof was shorn and the pickup’s front tires came down on the car’s back seat, where the three children were sitting. “They were crushed,” a police official said.

Authorities said the siblings’ parents were hospitalized in critical but stable condition.

“The actions of a suspected drunk driver have ended in a lifetime of pain for this family,” Stawinski said in a statement Monday. The driver of the pickup was briefly taken into custody for sobriety testing, then released pending the outcome of an investigation.

“We work tirelessly to clear our roads of drivers who make the horrible decision to pick up their keys and drive while impaired,” the chief said. “So it is difficult to describe how deeply frustrated I am, because, despite all of this work, a family is suffering beyond imagination.”

The children, who lived with their parents in Falls Church, Va., were identified by authorities as Alexander and Rosalie Mejia, both 5, and their younger brother Isaac, whose first birthday was in November. The three “were killed upon impact,” police said.

A police department official, speaking on the condition of anonymity because of the investigation, said authorities expect to eventually file charges against the driver of the pickup, who has not been publicly identified.

“We could have charged him [Sunday] night” with drunken driving, the official said. In that case, however, “he’d just go to court, pay his fine, and go on his way” while the investigation, which could take months, was still in process.

If the investigation later produced evidence warranting more serious charges, such as multiple counts of manslaughter, authorities would be barred from prosecuting him because of the legal concept of double jeopardy, the official said.

“While it is early in our investigation,” police said in a statement, “we know the crash occurred just before an intersection where the family was either slowed or stopped behind two other vehicles for the traffic light.” The family was in a Honda Accord.

“The driver of the pickup is suspected of driving under the influence and, it appears, was moving at a much higher rate of speed than the victims’ cars,” the statement said. “Preliminarily, there is no evidence of skid marks on the scene prior to the point of impact with the car carrying the family. The pickup truck came to rest on top of the rear-passenger compartment of that sedan.”

The police official familiar with the crash said it appeared that the youngsters were properly restrained in the back seat. But even if they had not been, “it wouldn’t have made a difference. The front tires [of the pickup] landed on top of them,” the official said.

Authorities said the investigation will look at numerous aspects, including witness interviews, toxicology tests, a detailed crash reconstruction and an examination of the pickup’s mechanical condition.

Prince George’s State’s Attorney Aisha Braveboy said that when “a thorough and complete investigation” is finished, her office “will work diligently to determine the appropriate charges that should be filed.”

In a similar case in Prince George’s, five people, including a baby, were killed in a crash in Oxon Hill on Oct. 10, 2014. Seven months went by before the motorist who caused the tragedy was indicted by a grand jury and arrested.

Four of the victims — sisters Typhani Wilkerson, 32, and Tameika Curtis, 35; Khadija Ba, 13; and 1-year-old Hassan Boykin — were passengers in an Acura being driven by the sisters’ mother, who was critically injured.

The car was stopped at a red light shortly after 9:30 p.m. when it was rear-ended by a Mercedes-Benz that authorities later said was traveling 70 mph in a 30 mph zone.

A passenger in the Mercedes, Dominque Green, 21, also died.

The driver of the Mercedes, Kenneth Kelley, then 26, had a blood alcohol level of 0.14, nearly twice the legal limit for driving in Maryland, police said.

But Kelley, of Southeast Washington, was not arrested that night. Instead, after a long investigation, he was indicted in May 2015 on more than two dozen criminal charges.

In June 2017, after Kelley pleaded guilty to five counts of negligent manslaughter and other offenses, he was sentenced to 50 years in prison.

Maryland state Sen.-elect Obie Patterson (D-Prince George’s) said the stretch of road where the crash occurred is notoriously hazardous, even for drivers who are not impaired. The road is a long straightaway conducive to high speed.

Because of construction on Indian Head Highway, the area is even “more dangerous” because of a lack of lighting and other problems, Patterson said.

At a recent meeting with state highway officials, “I told them they need to do something,” he said.

The county just installed the first red-light camera on the highway. Patterson, a former Prince George’s County Council member, said he has been arguing for years that multiple red-light cameras are needed along the road.

Julie Tate and Keith L. Alexander contributed to this report.