GULFPORT (AP) — Harrison County’s sheriff says a teenager who had been on suicide watch hanged himself in the short time between deputies’ rounds.

Sheriff Melvin Brisolara says 17-year-old James Mack Allen of Gulfport was found hanging in his cell on Christmas Eve. Allen died Christmas Day. Allen had been arrested Tuesday and charged as an adult with vehicle burglary.

Officials say the teen tried to kill himself Monday and left a suicide note for his father.

Brisolara says only 17 minutes had gone by since a guard had last checked on Allen. The sheriff also said it’s impossible to watch jail inmates 24-7, even when overcrowding isn’t a problem.

There were 927 inmates on the Harrison County Jail’s roster.