The inquiry, which is being conducted by lawyers in the office’s charities bureau, follows a yearlong series by ProPublica that revealed how some guardians neglected the vulnerable clients entrusted to their care, while others used their court-appointed positions to enrich themselves at their wards’ expense.

Judges often rely on guardianship companies to care for the so-called unbefriended, people who don’t have friends or family able to look after them. Oversight of these guardians, however, is scant, with officials rarely visiting wards to check on their care. Meanwhile, the courts that appoint the guardians rely largely on financial paperwork to determine a person’s well-being. That dynamic, the news organization found, has resulted in fraud, abuse and neglect of the state’s most vulnerable.