FALL RIVER, Mass. — A police department in Massachusetts told prosecutors it lost at least two years of evidence for drug cases.

WPRI-TV reports that Fall River Interim Chief Paul Gauvin sent a letter to Bristol County District Attorney Thomas Quinn in late March, informing his office that controlled-buy logs for 2019 and 2020 are missing. The information was relayed to defense attorneys and Quinn said he’s now investigating the matter.

The district attorney’s office said it’s too early to estimate how many cases might be affected.

Gauvin wrote in the letter obtained by WPRI that the loss of evidence is “inexcusable and an embarrassment” to the Fall River Police Department.

Fall River police said they knew the log books were missing for nearly a year, but only notified the district attorney’s office last month after the information was requested in a court case.

The logs are kept to show how detectives purchased illegal drugs from suspected dealers by going undercover or using informants. The information is often used to obtain search warrants and support court cases.

The department said Wednesday that it’s “undetermined” if the log books were stolen and it’s investigating. The department plans to use a secure intranet system to record the information instead of log books.