Daniel Penny's martial arts instructor from the Marine Corps took the stand Thursday for day six of witness testimony in Penny's trial in the chokehold death of Jordan Neely.

A former Marine combat instructor testified that Daniel Penny misused a combat maneuver when he fatally choked Jordan Neely aboard a Manhattan subway, saying he appeared to have attempted a “blood choke” and should’ve known to let go after Neely lost consciousness.

New video shows the statement Daniel Penny gave to investigators after placing Jordan Neely in a deadly chokehold on a subway last year.

The military trainer said that Marines are taught to render a person unconscious in seconds. Mr. Penny held Jordan Neely, a homeless man, for six minutes.

A former military combat instructor says a fellow Marine veteran misused a combat move when he fatally choked a homeless man on the New York subway.

Joseph Caballer, a nine-year veteran of the corps who trained troops in self-defense, told the jury Daniel Penny's elbow and hand were "not in the correct position" for a proper figure-four chokehold and he could have been cutting off Jordan Neely's windpipe.

Daniel Penny's martial arts instructor from the Marine Corps took the stand Thursday for day six of witness testimony in Penny's trial. The Marine veteran is accused in the chokehold death of Jordan Neely on the subway last year.

Penny held Neely in a chokehold for about six minutes — including for more than 50 seconds after Neely stopped moving — according to evidence presented in his criminal trial.