A pedestrian passes by a Las Vegas Metro Police patrol car at Westland Plaza, a medical office building that includes the Las Vegas offices of Michael Jackson's personal doctor Conrad Murray, July 28, 2009. Authorities entered the medical office as part of a manslaughter investigation into Michael Jackson's death.[Agencies]

LAS VEGAS - Police seized cell phones and a computer hard drive from the Las Vegas home and office of Michael Jackson's personal physician on Tuesday as the probe into the pop star's sudden death focused increasingly on the doctor who was at his side when he died.

It was the second raid on Dr. Conrad Murray's offices in less than a week as officials seek evidence into the cause of the "Thriller" singer's death of cardiac arrest on June 25.

Murray's lawyer, Ed Chernoff, said after the first raid in Houston last week that police and Drug Enforcement Administration agents were looking for "evidence of the offense of manslaughter."

On Tuesday, Chernoff said authorities in the Las Vegas raid were looking for "medical records relating to Michael Jackson and all of his reported aliases."

Chernoff said in a statement that Murray was present during the four-hour search of his house "and assisted officers. Investigators left Dr. Murray's home ... seizing cell phones and a computer hard drive."

Authorities appear to be focusing their efforts on Jackson's use of prescription drugs, particularly the anesthetic propofol, and Murray's possible involvement in providing it.

Media reports have said Jackson used numerous aliases over the years to get hold of a range of powerful prescription drugs.

Drug Enforcement Administration officials said they were looking for documents at Murray's Las Vegas house and office but declined to be more specific.

Last week's search at Murray's office in Houston yielded information from a computer hard drive, billing and medical records, vials of medication, a Rolodex card and other objects, according to court documents cited in media reports.

TOXICOLOGY REPORT

Los Angeles coroners have said they expect to issue a report into the cause of Jackson's death as early as this week, following toxicology reports.

Since Jackson's death, investigators have questioned and searched the offices of other doctors who treated him over the years, as news media reports have said the probe into his death is focused on his use of propofol to sleep.

Murray was Jackson's personal physician in the weeks before he died and was at his bedside trying to revive the pop star before he was taken to a Los Angeles hospital where he was pronounced dead.

Celebrity website TMZ has reported that Murray told Los Angeles police that he had administered propofol to Jackson only hours before he died, but that could not be confirmed officially.

The drug, which is sold under the trade name of Diprivan and used as an anesthetic for surgery, is only supposed to be used under doctor supervision.