Federal agents say the owner of Dallas' iconic Italian restaurant Campisi's is a large illegal sports bookie with ties to internet bookmaking websites in Costa Rica, according to a search warrant mistakenly unsealed by prosecutors and obtained by NBC 5.

According to the document, in February agents for Homeland Security Investigations and the criminal division of the IRS searched safety deposit boxes belonging to David Campisi, the restaurant owner and great-grandson of its founder.

They also searched the home of an alleged Campisi associate, Christopher "Gus" Schraeder, who has since pleaded guilty to a single illegal gambling charge.

Schraeder, who lives in Fort Worth, admitted he operated as a bookie with at least five other people in an operation that brought in at least $2,000 per day. He faces up to five years in prison and a $250,000 fine. A sentencing date has not been set. His plea agreement with prosecutors remains sealed.

Campisi has not been charged or arrested. His attorney, Michael Uhl, said he had no comment.

A spokeswoman for the U.S. Attorney's office in Dallas declined to talk about the status of the investigation.

A call to a number identified in the search warrant as Schraeder's cellular phone was answered by a message saying his voice mail was not set up. He did not respond to a text message. His attorney, federal public defender Frank Henderson, did not return a phone call.

'Large Bookmakers'

The search warrant, signed by an HSI agent, describes Campisi and Schraeder as "large bookmakers operating in the Dallas and North Texas area" since at least 2005.

Cellphone records cited by law enforcement show the two had numerous contacts with Costa Rican telephone numbers linked to offshore internet-based sports websites.

From November 2015 until September 2018, Campisi called or texted the Costa Rican numbers 190 times and Schrader more than 300 times, the warrant said.

The investigation started after a separate 2012 probe which targeted 20 bookies linked to an illegal gambling operation that took in more than $5.4 billion from 2007 to 2011, according to the warrant. All 20 suspects in that case pleaded guilty to crimes ranging from money laundering to tax violations, according to court records.

During the course of the 2012 investigation, Campisi and Schraeder were identified as "large bookmakers operating in the Dallas and North Texas area," the agent wrote, adding that records seized at one of the suspect's homes "reflected that Campisi and Schraeder were partners in the conduct of their illegal gambling enterprise."

Past 'Mafia Mystique' and Ties to Jack Ruby

Campisi's was opened in 1946 by David Campisi's great-grandfather who had immigrated from Sicily, according to the restaurant's website. The family opened its location on Mockingbird Lane in 1950 and later expanded. Campisi's now operates seven restaurants in Dallas, Fort Worth, Plano, Frisco and Rockwall.

According to a 1999 story by The Associated Press, gangsters used to hang out at the restaurant and the family acknowledged that Joe Campisi was a "golfing and racetrack buddy" of New Orleans Mafia boss Carlos Marcello.

"They were friends. He just knew everybody," David Campisi was quoted as saying about his grandfather.

The younger Campisi said he regretted not capitalizing more on the restaurant's "mafia mystique."

"Today bad publicity is just as good," David Campisi told the AP. "I think to us it's more comical than anything, but the public always ate it up. We've never played off it like we should."

Campisi's own website accurately notes that Jack Ruby ate dinner at the restaurant the night before President John F. Kennedy was assassinated in Dallas in November 1963 and that Joe Campisi visited Ruby in jail after Ruby shot and killed assassin Lee Harvey Oswald.

The meetings became fodder for unconfirmed conspiracy theories about mob involvement in the Kennedy assassination.

Nothing suggests David Campisi or anyone else currently associated with the restaurant has mafia ties.

Search Warrant Mistakenly Released

The February search warrant naming Campisi and Schraeder was obtained by NBC 5 from the federal court website known as Pacer after it was made public by mistake in early October, apparently by a prosecutor who intended to unseal an unrelated search warrant and transposed the case number.

"The document in question was unsealed inadvertently by the Northern District of Texas," said Erin Dooley, spokeswoman for the U.S. Attorney in Dallas. She declined further comment.

Federal prosecutors re-sealed the search warrant after NBC 5 asked about it.