Complex sentence: It was later picked up by a fourth hitman, Joseph Sullivan, it has been asserted that he sealed the body in an oil drum and buried it underneath Giants Stadium, however no evidence has ever been found to substantiate this claim.
Split into simpler sentences: It was later picked up by a fourth hitman, Joseph Sullivan. It has been asserted that he sealed the body in an oil drum and buried it underneath Giants Stadium, however no evidence has ever been found to substantiate this claim.