Implicate = "to show" that someone is involved in crime
Implicate also = to imply indirectly that someone is involved in a crime "indirectly" rather than saying it clearly in normal language.
Incriminate = make someone appear to be guilty by what you say or do,
incriminate also = to charge with a crime or show evidence of proof of a crime.
Most of the time they can be interchanged. Most often used to describe crime guilt or wrong doing, although it does not always have to be so.
"The defendant refused to speak to the police for fear of incriminating himself".
"The witnesses testimony clearly implicates the defendant as being involved in the crime for which he has been brought before this court"
"I saw you running down the road shortly after Mrs smith's body was discovered at her home"
"what are you incriminating me in the crime?" or
"what are you trying to implicate me with?"
(some speakers would say implicate some incriminate in this sentence).
in common parlance it would be
"what are you saying? or what are you implying? or what are you accusing me of"
implicate incriminate would mostly be used by the courts, police, media outlets, TV news, newspapers