Political Science Professor Tim Groseclose resigned Thursday from UCLA's Committee on Undergraduate Admissions and Relations with Schools and said he was being blocked from investigating a "cover up," the Los Angeles Times reported Saturday.

"A growing body of evidence strongly suggests that UCLA is cheating on admissions," Groseclose said in a lengthy UCLA Web site posting. He argues the school was illegally admitting African-American students at the expense of others, including Vietnamese Americans.

The university categorically rejected Groseclose's claims, saying he hadn't factored in increased outreach before admissions decisions.

California Proposition 209, approved in 1996, bars public universities from using race and other factors such as religion in admissions decisions. Since then the number of black students had dropped dramatically. In 2006, only 103 freshmen and 108 transfer students at UCLA were African-American. But this year numbers increased to 230 black freshmen along with 100 transfer students.