LONDON (AP) — British police say as many as 10,000 criminal cases may have been affected by alleged data manipulation at a forensics laboratory.

Two people have been arrested by police investigating claims of tampering with results at Randox Testing Services, a company that tests samples for police.

The National Police Chiefs' Council said Tuesday that three-quarters of the cases identified were traffic offenses such as driving while under the influence of drugs. Others include violent crimes and unexplained deaths.

Some 50 cases have been dropped as a result of the investigation — some after samples were retested and others because samples were no longer available.

Gillian Tully of Britain's Forensic Services Regulator said she could not give details of the allegations because of the police investigation, "but we cannot just say it was a minor technical issue."