Federal agents raided homes in Los Angeles and Miami on Monday that are connected to the hip-hop mogul Sean Combs, a person with knowledge of the case said.

Homeland Security Investigations carried out the raids but did not provide details about the case, including whether Mr. Combs was a target or which criminal charges were being investigated. Mr. Combs, who is also known as Puff Daddy or Diddy, has been accused of sexual assault and sex trafficking in multiple civil lawsuits over the last several months.

A spokesperson for Mr. Combs did not respond to a request for comment.

The criminal inquiry was being conducted by federal prosecutors in the Southern District of New York and federal agents with Homeland Security, a law-enforcement official said. Nicholas Biase, a spokesman for the Southern District, declined to comment.

In a statement, Homeland Security said that agents from New York had “executed law enforcement actions as part of an ongoing investigation, with assistance from HSI Los Angeles, HSI Miami and our local law enforcement partners.”

Video from Fox 11 (KTTV), a local television station in Los Angeles, showed armed officers entering a home in the Holmby Hills area of the city, which a law-enforcement official said was connected to Mr. Combs. Public records in California also indicate that the home is owned by a company led by Mr. Combs.

The raids were a stunning development in the career of Mr. Combs, 54, a producer, label executive and occasional rapper who has been one of the most influential and widely recognized figures in the music business over the last 30 years.

He played an integral role in the transformation of hip-hop into a global commercial force, crafting hits and larger-than-life personas for rap and R&B performers like the Notorious B.I.G. and Mary J. Blige. He also made smash hits himself with songs like “I’ll Be Missing You” (1997), a ballad to the Notorious B.I.G. after his killing in a drive-by shooting, which featured Faith Evans, the rapper’s widow, and sampled the Police’s hit “Every Breath You Take.”

But Mr. Combs has also been dogged for decades by accusations of violence. In November, he was sued for sexual assault by Casandra Ventura, his former girlfriend, who was also signed to his label, Bad Boy, as the performing artist Cassie.

In her suit, Ms. Ventura accused Mr. Combs of forcing her to engage in sexual activity with male prostitutes over a period of years. The suit said that as a result of those encounters, which took place in a number of cities across the United States, Ms. Ventura was a victim of sex trafficking.

Ms. Ventura’s civil suit was settled in just one day, with her and Mr. Combs saying their dispute had been resolved “amicably.”

That case, filed in a detailed 35-page complaint, drew headlines around the world and imperiled the business brand he had steadily built up over decades. In the months before Ms. Ventura’s suit, Mr. Combs was given industry awards and released his first studio album in 17 years.

Even after its settlement, Ms. Ventura’s suit was followed by several more cases, each accusing Mr. Combs of sexual assault. In one case filed last month, a music producer, Rodney Jones, said that Mr. Combs had made unwanted sexual contact with him, and forced him to hire prostitutes and participate in sex acts with them. In recent months, many of Mr. Combs’s business partners have distanced themselves from him.

Federal investigators in New York have been leading the investigation, and have been conducting interviews asking potential witnesses about sexual misconduct allegations against Mr. Combs for several months, according to a person familiar with the interviews.

Mr. Combs has denied the accusations against him. In December, after an anonymous woman filed a suit accusing Mr. Combs and two other men of raping her in a New York recording studio in 2003, when she was 17, the music mogul said: “Sickening allegations have been made against me by individuals looking for a quick payday. Let me be absolutely clear: I did not do any of the awful things being alleged.”

After Mr. Jones’s suit last month, Shawn Holley, a lawyer for Mr. Combs, said Mr. Jones is “nothing more than a liar who filed a $30 million lawsuit shamelessly looking for an undeserved payday,” and called his accusations “pure fiction.” Ms. Holley and two other lawyers for Mr. Combs also did not respond to requests for comment on Monday.

In a statement on Monday, Douglas Wigdor, a lawyer who represents Ms. Ventura and the anonymous woman who sued Mr. Combs alleging the assault at a New York studio, said: “We will always support law enforcement when it seeks to prosecute those that have violated the law. Hopefully, this is the beginning of a process that will hold Mr. Combs responsible for his depraved conduct.”

The home searched in Miami was on Star Island, an exclusive enclave of mansions in Biscayne Bay popular with celebrities and the wealthy. On Monday its usual tranquillity was interrupted by a Homeland Security Investigations van with flashing red-and-blue lights, law enforcement officials in blue windbreakers and at least two agents with dogs, as well as journalists dotting its palm-lined lawns.

A similar scene played out near Mr. Combs’s home in Los Angeles, where by late afternoon a few dozen people, many of them journalists, milled about the tony neighborhood of Holmby Hills, unable to cross the yellow caution tape strung across South Mapleton Drive.

A few Los Angeles Police officers blocked the road leading up to Mr. Combs’s property. Those passing took an interest, with drivers of luxury sport utility vehicles slowing down to take photos of the scrum.

The neighborhood, just a mile east of the University of California, Los Angeles, is accustomed to attention. Boasting a long list of celebrity residents, it is where Hugh Hefner once threw lavish parties at the Playboy Mansion and where Michael Jackson lived in a château just before his death. Most estates are surrounded by gates and greenery or vine-covered stone walls — pillars of privacy for a community known for its exclusivity.

Hamed Aleaziz contributed reporting from Washington, D.C., Chelsia Rose Marcius from New York, Corina Knoll from Los Angeles and Verónica Zaragovia from Miami.