The Minnesota Department of Public Safety is sounding the alarm about a dangerous new drug known as "Mexican Oxy," pills containing fentanyl that are now linked to fatal overdoses across the country — and at least one in Minnesota.

Beth Leann Roulet, 38, was found dead in her Mankato home Tuesday, apparently from an opioid overdose, authorities said. Investigators discovered small, light blue pills nearby with the letter "M" on one side and the number "30" on the other.

A lab test confirmed that the pills, which were marked to mimic legitimately manufactured oxycodone, contained fentanyl. Fentanyl is about 100 times as powerful as morphine, posing a serious risk of overdose.

"Counterfeit opioid drugs are designed to look like the real thing," said Drew Evans, Bureau of Criminal Apprehension superintendent. "Your supplier has no idea which dose would kill you, and neither will you. There is no safe dose."

The Minnesota River Valley Drug Task Force believes the drugs originated in Mexico and are responsible for a number of accidental deaths nationwide.

In recent years, investigators have focused efforts on targeting mid- to high-level drug dealers in an effort to make communities safer.

A Minneapolis dealer was convicted of third-degree murder Monday and sentenced to one year in the county workhouse for selling a fatal dose of fentanyl to a co-worker.

"We are trying to prevent any other tragedies from happening again," said Brian Marquart, statewide gang and drug coordinator.