The owner of the company whose two employees died when a trench collapsed and flooded last October is headed to trial on charges of manslaughter and impeding the police investigation into the deaths, authorities said.

Prosecutors say Kevin Otto of Blackstone knew the dangers of sending workers into a Dartmouth Street trench on Oct. 2, 2016 without any type of cave-in protections, and did it anyway. Otto's business, Atlantic Drain Services Inc ha been cited twice by the Occupational Safety and Health Administration for failing to utilize cave-in protections – first in 2007, when they were fined $15,000, and again in 2012, when they were fined $40,000. As a result, Atlantic Drain Services agreed to provide comprehensive training programs so workers understood the hazards to which they could be exposed while excavating.

RELATED: 2 construction workers die in collapsed flooded trench in South End 

As a result, Robert Higgins and Kelvin Mattocks became buried up to their waists as dirt began to slough off the sides of the 12-foot deep trench they were working in. When a fire hydrant fell into the hole, water began to pour in. The trench was flooded within seconds and neither Higgins nor Mattocks was able to escape. Both died at the scene, and it would be almost six hours before their bodies could be recovered.

When state prosecutors and OSHA subpoened records from Atlantic Drain Services, Otto allegedly falsified documents and intimidated witnesses, according to the Suffolk County District Attorney's office.

"[Atlantic Drain Services] submitted to OSHA various documents purporting to be sign-in sheets for excavating and trenching trainings, as well as documents regarding the receipt by workers of personal protective equipment,” Assistant District Attorney Lynn Feigenbaum said.

Investigations found the signatures on the documents were allegedly forged. 

Otto and his business where each indicted on two counts of manslaughter, one count of misleading an investigator under the state’s witness intimidation statute, and six counts of concealing a record under the evidence tampering statute. A trial is set for Feb. 5, 2018.