A Massachusetts man accused of locking a Verizon worker inside an unventilated underground vault because he was upset the worker parked on his grass has pleaded guilty to kidnapping.

Westborough resident Howard Cook Jr. entered the plea Tuesday in Worcester Superior Court.

The 73-year-old Cook was sentenced to a year of probation and ordered to complete an anger management program.

Authorities said the retired utility official locked Michael Hathaway in the vault in August 2013 by pulling out the extension ladder, locking the hatch and placing large rocks on top. The ventilation system automatically shuts off when the door is closed.

Police said Cook was upset that Hathaway parked on the grass at his business.

Hathaway used his cellphone to call police.