Don Gawick, who is currently the COO of C&J Energy Services Ltd., was appointed as the president and CEO by the board of directors, replacing Randy McMullen in the roles, the company said June 15.

Gawick will also continue working as COO, a position he has held since 2012. He has worked in oilfield services for 37 years, beginning at Schlumberger Ltd. in 1979. Throughout is career he has held several senior management positions.

Previously, he was president and CEO of Casedhole Solutions Inc., a wireline services company that C&J acquired in 2012.

McMullen became president and CEO of the well completion and construction services company after the unexpected death of CEO Joshua E. Comstock. Comstock died in March at age 46. At the time, the forensics office in Harris County, Texas, where he died, said the cause of death was not determined.

C&J said that McMullen also stepped down as CFO and as a board member. Mark Cashiola will replace him in that role. Cashiola joined C&J in January 2011 and has been vice president – controller and chief accounting officer.

Cashiola has more than 18 years of finance and accounting experience, most of it in the energy industry. He previously worked for Arthur Andersen LLP and KPMG LLP.

Also, C&J said that Danielle Hunter became executive vice president, general counsel and chief risk officer following the departure of Ted Moore from those roles.

Hunter joined C&J in June 2011 and has been vice president – corporate and compliance and associate general counsel. Prior to joining C&J, Hunter worked at Vinson & Elkins LLP from 2007 through 2011.