A routine traffic stop for illegally tinted windows last week led a Bensalem drug-sniffing police dog to discover more than 13 pounds of heroin valued at $4 million.

The seizure of six kilograms occurred Friday. Bucks County District Attorney Matthew Weintraub said the bust of "400,000 doses of death" was the largest he could recall in recent county history.

"It is much more preferable for me to stand here before you today to celebrate getting these doses of death off the streets," Weintraub said, "than it is to come before you again and again to lament how many of our children are being killed by this poison."

Authorities said they were investigating where the occupants of the car came from and where they were heading, as well as doing forensic testing on the heroin to determine its origin.

The drugs were discovered after Bensalem police spotted a white Toyota Tacoma with illegally tinted windows in the area of I-95 and Street Road.

The stories the three occupants told police didn't make sense, authorities said, leading officers to enlist the department canine to search the truck.

The dog alerted police that narcotics were present. When police told the occupants, driver Edward Torres, 30, of Philadelphia, who wore an ankle bracelet, ran. Police later discovered he was on house arrest for a robbery and firearms violation.

Inside a hidden compartment underneath the back seat of the truck, officers discovered the six kilograms of raw heroin in bricks, police said.

Torres was arrested for drug trafficking, as were passengers Sergio Arturo Maciel Landeros, 27, and Alejantro Levya Granados, 41, both of whom had no fixed addresses but were from the Philadelphia area, according to police.

Police then focused their search on a home at 6215 Algard St. in Philadelphia, where they said they discovered $50,000 and drug paraphernalia. They would not elaborate on what led them to that residence or who lived there.

All three men were being held Thursday in the Bucks County Prison on $1 million bail each.

Torres maintains his innocence, said his attorney, Jason Javie, who said he could not comment further about the case.

No attorneys for Maciel Landeros and Levya Granados were listed on court documents as of Thursday.

In Bucks County in 2016, opioid overdoses killed 185 people, twice as many as the year before.

The announcement of the bust occurred two days after Montgomery County announced the seizure of one kilogram of fentanyl, a painkiller said to be much stronger than heroin, and a week after Montgomery County joined Philadelphia and Delaware, Chester, and Camden Counties as a nationally recognized High-Intensity Drug Trafficking Area.

As the national opioid crisis continues, Weintraub said, he is looking into how Bucks County can apply for that designation, which comes with federal money, resources, and training to combat drug-related crime.

"It is something we have been interested in for a long while," Weintraub said. "We're not yet a member, but if I get my way we soon will be."