Three bodies were recovered Thursday morning from a manure pond at a dairy near Kennedyville, Md.  

The victims were a father and two sons, aged 48, 18 and 14.

According to WBAL Radio, other farm workers found a tractor parked and still running near the manure pond where the three had been working. Read more.

And, family members became concerned when the three did not arrive at home to milk their own cows Wednesday night.

Autopsies revealed that all three victims died of asphyxia (or deprivation of oxygen). The 14-year-old had an additional cause of death listed as multiple injuries, which investigators believe were inflicted by the large propeller on the end of the auger that circulates the liquid manure in the pit, according to CBS 21 in Harrisburg, Pa.