A MetroAccess driver has been accused of sexually assaulting a disabled rider while transporting her home from adult day care in at least the third sexual assault case involving the agency's paratransit service so far this year.

Authorities were still looking for the man as of Tuesday evening on one count of second-degree rape and two counts of second-degree sexual offense. The California contractor that provides the service to Metro identified him as Tanveer Fayyaz. a_data>

A MetroAccess rider reported on Monday that the driver who picked her up at an adult day care center assaulted her in Montgomery County on Thursday as she made her way home, according to Metro.

Fayyaz, who had been driving MetroAccess riders since January, was suspended from the service, according to MV Transportation and Metro. He does not work for Metro directly; he drives for Regency Cab, a subcontractor of the MV Transportation service that provides the shared rides for Metro passengers with disabilities.

Fayyaz could not be reached Tuesday evening. Regency Cab did not return calls for comment.

The case was at least the third in the past seven months. The first case in January did not result in criminal charges against the driver, but he was fired. The second also occurred in January but the driver was not criminally charged until April.

MetroAccess has been a sore point for the agency. It is a federally mandated service under the Americans with Disabilities Act for those physically unable to take Metrorail or ride Metrobus. But riders have long complained about the level of service -- and even won a class-action lawsuit againstMetro. Its ballooning costs of about $38 per ride have contributed to Metro's fiscal instability.

The service also has been plagued with high turnover. A 2008 independent report commissioned by the Metropolitan Washington Council of Governments found that MetroAccess had a 111 percent turnover rate among drivers, more than triple the national average of about 30 percent.

Before a driver can begin running trips for MetroAccess, he or she must undergo a criminal background check, MV spokesman David Smith said. He could not provide particulars Tuesday but said generally that any felony charges would eliminate a job candidate. After one year of service, all drivers undergo a second background check.

In this case, Smith said, Fayyaz had a valid taxi permit when he was hired to drive MetroAccess riders. MV Transportation did not conduct the background check, but Smith said drivers receiving such permits undergo background checks "as thorough if not more thorough" than those done by MV. Fayyaz would not have been with the agency long enough to have undergone the second check.

After the second case, Smith said MV did a "full retraining" of all its MetroAccess drivers -- whether employees or subcontractors -- about the appropriate code of conduct. Fayyaz apparently would have undergone such training, Smith said.

Metro spokesman Reggie Woodruff said Tuesday that transit agency officials plan to meet with MV "to determine what followup actions should be taken."