A Bensalem Township police officer on routine patrol with his K-9 dog made one of Bucks County's  biggest drug busts on Sunday, seizing heroin and methampehamine worth $11.7 million, authorities said Monday.

The 15 kilos of heroin and 20 pounds of "very pure crystal methamphetamine" were not earmarked for Bensalem, "but they were earmarked for the Delaware Valley," township Public Safety Director Fred Harran said at a news conference.

"I can't imagine how many lives were saved last night of people overdosing on this stuff," Harran said, with the plastic-wrapped bricks of drugs lined up neatly in front of him. "There's a lot of people not going to get high this week."

The drugs were found after Officer Brian Cowden, a 10-year veteran of the force, pulled over a tractor-trailer with California license plates and registration on Street Road, and his police dog, Edo, sniffed out the narcotics, Harran said.

The driver, Estaban Zalazar Velasco, 35, of Galt, Calif., and passenger, Juan Ledesma-Nolasco, 48, of Livermore, Calif., were arrested and arraigned before District Justice Joanne V. Kline. They were each being held Monday on $1 million bail in Bucks County Prison, on felony charges of criminal conspiracy and the manufacture, delivery, possession and intent to deliver controlled substances.

Cowden "was in the right spot, saw something he didn't like, and moved on it," Harran said.

The officer was on an "unrelated detail" at State Road and American Drive when he saw the two men "walking around suspiciously," Harran said. After they drove off in the 18-wheeler, Cowden noticed several vehicle violations and pulled them over, Harran said.

Edo, a 2 ½-year-old Belgian Malinois trained to detect narcotics, sniffed out the heroin and methamphetamine in the truck's sleeping compartment, Harran said.

The heroin has a street value of $9 million, and the methamphetamine is worth $2.7 million, Harran said.

The methamphetamine appeared to have come from Mexico, he said. "It's not typical Pennsylvania methamphetamine."

Police are still investigating where the drugs came from and the route the two suspects took to Bensalem. The tractor-trailer was being held in the police department's impound lot.

"These kinds of drugs are the reasons for the shootings, beating and robberies you see on the news every night," Harran said. "This is going to put a dent in someone's business."

In 2009, Cowden received the county's Outstanding Police Performance Award from the Citizen's Crime Commission of the Delaware Valley. At that time, he had confiscated more than $500,000 used in illegal narcotics traffic, plus drugs "that were passing through our township for distribution in the Delaware Valley," according to Bensalem's newsletter.

Cowden was not available for comment.