President Dmitry Medvedev on Wednesday ordered Interior Minister Rashid Nurgaliyev to investigate a fatal car crash involving a LUKoil vice president that caused public outrage over a perceived police cover-up.

Earlier in the day, a group of well-known cultural figures signed an open letter to Medvedev asking him to personally oversee an investigation into the accident, which killed Olga Alexandrina, 35, and her 72-year-old mother-in-law, Vera Sidelnikova.

"The president ordered Interior Minister Rashid Nurgaliyev to sort it out and report back on all of the circumstances of this tragedy," Medvedev's press secretary, Natalya Timakova, told reporters.

The order comes at a difficult time for Nurgaliyev, who must report back to Medvedev by the end of the month with plans for a sweeping reform of his scandal-ridden ministry. This is also at least the third time in recent months that Medvedev has personally intervened in a law enforcement controversy.

"In recent years, a double standard has reigned over our country's roads, and people driving cars with special license plates and special signals have become a constant and unpunished threat to ordinary drivers," the open letter said.

A copy was posted on the web site of lawyer Igor Trunov, who is representing the family of the women killed in the car crash, and the Federation of Russian Car Owners, which is conducting its own investigation into the accident.

On Feb. 25, LUKoil vice president Anatoly Barkov's Mercedes S-500 collided head-on with a Citroen C3 driven by Alexandrina. She and Sidelnikova were killed, while Barkov and his driver sustained minor injuries.

Police initially said Alexandrina was responsible for the accident, hitting Barkov's vehicle after pulling into oncoming traffic. But witnesses found by the driver's federation — several of whom have said they are willing to testify in court — said the Mercedes crossed the center line, causing the crash.

Russian media and bloggers have noted that the Mercedes was more likely to have pulled into the oncoming lane because it was traveling on the traffic-clogged side leading to downtown, while the Citroen was on the relatively empty side.

Barkov, who oversees security for LUKoil, has called for a thorough investigation. LUKoil, the country's largest private oil producer, has said it believes the initial version set forth by the traffic police.

Trunov, the family's lawyer, has said as many as 15 video cameras should have recorded the crash near Gagarin Square, in southern Moscow, but only one blurry video has so far been released.

The open letter accused police investigators of covering up details of the crash to protect Barkov, alleging that the license numbers on his car were changed at the scene and that the investigator assigned to the case is refusing to give the victims' families access to the case materials.

Medvedev has made fighting corruption — and more recently, a reform of the much-maligned Interior Ministry — a signature issue of his presidency. In recent months, he has also intervened in public scandals involving abuses of authority, and so far with considerable effect.

In February, Medvedev ordered prosecutors to look into the demolition of homes in the Moscow neighborhood of Rechnik, which was widely perceived as a selective application of justice over a years-long zoning dispute.

Court marshals — with heavy encouragement from the Moscow City Hall — have stopped the demolitions and city authorities are now facing criticism for overstepping their authority in the dispute.

Medvedev was also the first senior government official to weigh in on the November death of lawyer Sergei Magnitsky, who was repeatedly denied medical care during almost a year of pretrial detention on politically tainted tax charges.

Several prison officials were subsequently fired after Medvedev ordered an investigation and Justice Minister Alexander Konovalov, a top Medvedev ally, promised to root out corruption in the prisons system.