 -- The family of a California man who was killed Sunday night during the mass shooting in Las Vegas is petitioning a court to freeze the gunman's assets.

The gunman, identified by police as 64-year-old Stephen Paddock, opened fire on a musical festival crowd from the 32nd floor of the Mandalay Bay Resort and Casino in Las Vegas on Oct. 1, killing 58 people and injuring 489 others before taking his own life. More than 22,000 people were attending the final night of the Route 91 Harvest Festival when gunfire erupted.

John Phippen, 56, was among those shot and killed, according to Clark County coroner John Fudenberg. The father of six from Santa Clarita, California, was in the crowd with his adult son, Travis Phippen, who was injured, ABC station KABC in Los Angeles reported.

Attorneys for Travis Phippen filed a petition in the Clark County District Court on Friday asking the judge to appoint Clark County Public Administrator John Cahill to oversee Paddock's estate so the Phippen family and others who "suffered loss, distress and injuries" can pursue lawsuits against the estate. The petition also asks that Cahill have the authority to marshal and take possession of Paddock's assets for "safe keeping," according to court documents obtained by ABC News.

The move would block Paddock's longtime girlfriend, Marilou Danley, his brother, Eric Paddock, or any other possible heirs from transferring his money.

"We have filed a petition with the district court in Nevada, requesting that the court appoint a public administrator of the state of Nevada to take control of his assets," attorney Richard A. Patterson of the California law firm Owen Patterson & Owen said in a recent interview with KABC. "It is for the benefit of everyone. It will preserve the asset subject to the court's direction and future distribution."

Paddock’s finances and recent transactions have become a key focus for investigators trying to piece together more about the Mesquite, Nevada, resident and why he launched the deadliest mass shooting in modern U.S. history.

More than 200 reports about Paddock’s activities, particularly large transactions at casinos, have been filed with law enforcement authorities in the past three years alone, ABC News has learned.

While some of the reports centered around "suspicious activity," most were "currency transaction reports," which casinos are required to file with the U.S. Department of Treasury's Financial Crimes Enforcement Network, or FinCEN, when someone withdraws or deposits more than $10,000 in cash.

The number of reports prompted by Paddock's activities suggest he often gambled with large amounts of money.

In one case, Paddock recently won $40,000 on a slot machine, his brother, Eric Paddock, told The Associated Press. Eric Paddock described his brother as a multimillionaire, and said they had business dealings and owned property together.

When asked about the reports associated with Paddock, a FinCEN spokesperson told ABC News the agency "does not comment on specific reports filed by financial institutions," but added, "FinCEN provides access to its database to authorized law enforcement and regulatory users and the data has proven to be extremely useful to investigators."

ABC News' Mike Levine contributed to this report.