Vice President Mike Pence routinely used a private email account to conduct public business as governor of Indiana, at times discussing sensitive matters and homeland security issues.

Emails released to IndyStar in response to a public records request show Pence communicated via his personal AOL account with top advisers on topics ranging from security gates at the governor’s residence to the state’s response to terror attacks across the globe. In one email, Pence’s top state homeland security adviser relayed an update from the FBI regarding the arrests of several men on federal terror-related charges.

Cybersecurity experts say the emails raise concerns about whether such sensitive information was adequately protected from hackers, given that personal accounts like Pence’s are typically less secure than government email accounts.In fact, Pence’s personal account was hacked last summer.

Furthermore, advocates for open government expressed concerns about transparency because personal emails aren’t immediately captured on state servers that are searched in response to public records requests.