A pizzeria run by a “sweet old lady” in St. Paul’s Macalester-Groveland neighborhood was the target of criminal charges Friday, after its owner allegedly dealt in some very special ingredients.

Police grew suspicious when Papa Dimitri’s Classic Pizza and Ice Cream, at Hamline and Randolph avenues and adjacent Cretin-Derham Hall high school, sold fewer than a dozen pizzas in a week. No employees ate there, and despite the presence of pizza ovens, there didn’t seem to be any heat.

The mystery appeared solved when U.S. postal inspectors discovered that dozens of pounds of marijuana had been sent to the “restaurant,” as well as the home of its owner’s 82-year-old grandmother.

Four people who police say were associated with the pizzeria, including owner Ryan Dimitri Brooks Sr., 27; his mother, Rosalyn Mary Brooks, 61; grandmother Joyce Elaine Merkley, 82, and a woman he lived with, Lena Shalay Kirk, 24, all of St. Paul, were charged Friday with multiple felonies in Ramsey County District Court.

The charges include conspiracy to sell marijuana; cocaine possession; engaging in business of concealing criminal proceeds; and illegal possession of a handgun by a felon.

According to a criminal complaint, a “concerned citizen” in August approached St. Paul police, telling them that something wasn’t right with the restaurant at 466 S. Hamline Ave.

The tipster noted Papa Dimitri’s was “rarely open and does not seem to do much actual business.” Also, the tipster heard employees complaining about the heat not working, “which the concerned citizen thought odd,” given the presence of large pizza ovens. And rather than eating at the pizzeria, the employees typically ate at the nearby Nook restaurant.

Investigators started looking into the business, which was transferred to Ryan Brooks in 2010. State employment data listed no employees at the restaurant.

The complaint noted that a former Ramsey County correctional officer, who knew Ryan when he was in jail several years ago, said Brooks admitted to using a prior pizza parlor to launder money from drug dealing, and “he utilized pizza boxes and bags to deliver marijuana under the guise of making pizza deliveries.”

In November, police began watching Papa Dimitri’s. Brooks’ mother, Rosalyn Brooks, opened the place in “the late afternoon hours,” and over a course of six days, there were five customers and four deliveries.

Review website Yelp revealed a one-star average for the restaurant, based on two customer reviews.

Reviewers complained of orders that took 15 minutes to place and excessively long delivery times.

“I’ve defrosted better pizza on my engine block,” Yelp reviewer Eric K. wrote.

“It’s owned by a sweet old lady but I think she runs the place by herself,” wrote another reviewer.

Also in November, a postal inspector discovered that several packages sent to Papa Dimitri’s and the West Side home of Merkley, Brooks’ grandmother, contained dozens of pounds of marijuana.

Some were postmarked from California, and others, whose return addresses were supposedly from St. Paul, “went through Denver prior to delivery suggesting they all originated in California,” the complaint said.

Police executed a search warrant after going over the river to the grandmother’s house, in the 800 block of Ohio Street. She and Rosalyn Brooks were home, along with an unopened package.

When confronted with the package, Merkley said she had received three or four packages from her son containing marijuana and never opened them, “but she suspected what was inside.”

Rosalyn Brooks told police she worked at Papa Dimitri’s seven days a week delivering pizzas and co-owned the business.

Police found Rosalyn Brooks’ bank statement, showing $35,948.38 in deposits for one month in late 2014.

The Wells Fargo business account for Papa Dimitri’s received $189,891 in cash deposits between January and October 2013.

Investigators later determined that — despite being on parole — Ryan Brooks had traveled out of state 50 times since 2012.

In 2006, he and his mother had been arrested in Nebraska while returning to St. Paul from Las Vegas, with a rental car containing 107 pounds of marijuana in its trunk. Brooks served 90 days, and his mother wasn’t charged.

Ryan Brooks has four felony convictions, including multiple counts of assault.

Police later searched his mother’s North End home, in the 1000 block of Norton Street, and found two loaded handguns, several baggies of marijuana and paperwork showing she was going to receive a disability payment of $35,000.

A postal receipt in Ryan Brooks’ car from Santa Rosa, Calif., showed that he had mailed a 21-pound package to St. Paul from there.

Police searched his East Side home, in the 1600 block of Upper Afton Road, where he lived with Kirk and found a pound of marijuana.

Brooks was arrested during a December traffic stop while going to a meeting with his probation officer; he was later released.

A warrant was issued for the arrest of Brooks and Kirk after charges were filed Friday. They were not in custody as of Friday night. Brooks’ mother and grandmother were issued summonses to appear in court.

The restaurant was closed Friday evening, and Brooks could not be reached for comment. A woman who answered a phone number listed for Merkley immediately hung up.

Tad Vezner can be reached at 651-228-5461. Follow him at twitter.com/SPnoir.