A 62-year-old man, already tired from trying to save his drifting rental house boat, died Thursday after his dog jumped off the boat and he went went to save it.

David John, from Greenville, Texas, “appeared to be fatigued" after attempting to retrieve his houseboat that had detached from its anchor and was drifting in the Wahweap District of Lake Powell in the Glen Canyon National Recreation Area, near Page, Ariz., according to a news release.

Then, John’s dog jumped off the boat. John tried to save it and both disappeared in the water.

Onlookers kayaked out to John and brought him to shore. They tried CPR. Medics arrived later and couldn’t revive him. The dog survived.

A request for comment to a spokesperson for the national recreation area wasn’t immediately returned Saturday afternoon.

Kane County Sheriff’s Office and the National Park Service are investigating John’s death. The medical examiner will determine his official cause of death.

John is at least the fourth person to die at Lake Powell this month.

Albert Shortman, 33, likely drowned at Wahweap swim beach Aug. 11. A 15-year-old boy from Page, Ariz., drowned there on a school outing five days later. Jacob Jessop, 31, drowned Aug. 18 after getting tangled in underwater wires and cables at the Wahweap Marina.