翻译:汤姆与警方正在调查的这起棘手的案件有关

Tom is considered to be related to this troublesome case which the police was investigating.

楼上机译的吧……鄙视之

Tom is related to this hard case which is being investigated by the police.

Tom and the Police are investigating the effect of this difficult case

Tom is suspected to connect to an ongoing and complicated case of the police investigation.

Tom is relevant with the tough case which has been investigated by the police.