A synthetic drug purchased over the Internet has been identified as the likely killer of a Chanhassen High School senior found lying in a cattail marsh at Lake Minnewashta Regional Park over the weekend.

Alexander J. Snyder, 17, of Victoria, died Tuesday at Hennepin County Medical Center in Minneapolis.

His father called police just after 7 p.m. Sunday after realizing that his son was missing, police said Wednesday. He had used a tracking application on his son's phone to try to locate him at the park, where he found his son's phone sitting next to his discarded shoes.

Officers soon found the teenager, who was in the throes of a seizure, lying faceup in 3 to 4 inches of marsh water. He was taken to the Two Twelve Medical Center in Chaska and later to HCMC, where he died about 2 p.m. Tuesday.

A police investigation found that Snyder and a friend had purchased the drug online from China, according to the Carver County Sheriff's Office. The friend, from whom Snyder had become separated at the park, also was hospitalized after feeling sick from ingesting the drug. He was treated and released.

Authorities said they believe that the drug was dipropyltryptamine, a psychedelic drug sold on the Internet as DTP.

Alex's father, Jeremy Snyder, said Wednesday that his son, the youngest of his three children, loved his family and was always there for them.

"Alex was a wonderful person and absolutely brilliant," his father said in an e-mail. "He was awkward, but he embraced his awkwardness freely, and it became a part of his outstanding sense of humor."

He said his son will be buried next to his great-grandmother.

The news of Snyder's death hit hard at Chanhassen High School, where grief counselors were present for students Wednesday.

"Any time a student passes, it's tragic for students, staff and our families," said Principal Tim Dorway. "Our focus is on supporting students, family and staff in a way that meets their needs."

Drug use is not a new problem in the community, many students said in discussions on social media.

The Chanhassen Class of 2016 now has lost three students to drug overdoses, said junior Katherine Berkland, 16.

In 2013, Dylan Turcotte, 15, of Chanhassen, died of a heroin overdose. This past April, 17-year-old Macalob Bartram died in his Chanhassen bedroom, also of heroin toxicity.

Berkland said students are upset that more is not being done to prevent drug deaths.

"They only teach us about drugs in health class," she said. "I don't think that's enough."

Deadly experimentation

Young people's deaths often inspire an outpouring of warnings about the dangers of synthetic drugs. But as time passes, the warnings must be issued again.

In January 2014, Tara Fitzgerald, a 17-year-old at Woodbury High School, died after ingesting a synthetic drug known as 25i-NBOMe. She had been told it was LSD.

The Washington County attorney's office filed third-degree murder charges against three 17-year-old classmates of Fitzgerald, as well as two 19-year-old men farther up in the drug-selling chain. Evidence linking the defendants included thousands of text messages, and authorities publicly lamented the way social media was used to feed the youth drug culture.

The charges against the younger defendants were later downgraded as the result of plea agreements.

In April 2015, Alex Davis, 22, a University of North Dakota student from West St. Paul, died of an overdose of powdered fentanyl, another synthetic drug. Grand Forks police, citing his and other deaths in the area, said in online warnings that the drug was being sold and shipped online, and that users had no clue as to the purity or toxicity of the substances they were buying.

In August 2014, a new law took effect in Minnesota broadening the definition of synthetic drugs and empowering the state Board of Pharmacy to go after businesses that sell drugs that contain banned substances.

The measure was sponsored by two legislators from Duluth, a city that struggled for months to deal with complaints about a downtown head shop that sold synthetics. It included a provision for financial penalties against synthetic sellers who falsely claim their drug is legal.