Driving the wrong way down the one-way street, Mr. Watson pulled his own car, a BMW, in front of the agent’s car, partly blocking him in, the papers said. Then, Mr. Watson got out of his car and approached the agent with one hand hidden in the front pocket of his hooded sweatshirt, prosecutors said in a criminal complaint.

As the agent tried to maneuver around him, Mr. Watson pulled out a gun and opened fire, striking the agent once in his torso as he drove away, court papers said.

Though wounded, the agent managed to climb out of his car and fire back, hitting Mr. Watson at least once in his left hand, prosecutors said. Mr. Watson then fled in his car, abandoned it in a nearby auto body shop and sought treatment for his wound at Kingsbrook Jewish Medical Center. Prosecutors said he lied to doctors, telling them he had merely been a bystander to the shootout and was injured in the crossfire.

But law enforcement officers at the hospital later overheard Mr. Watson calling Ms. Gangapersad and telling her to go to their home, “get the jewelry and get rid of it,” court papers said.

When investigators interviewed Ms. Gangapersad that night, she initially lied about witnessing the shootout, court papers said. But she eventually confessed to having seen it, after the investigators confronted her with surveillance video that showed her on the front porch of the house with a clear view of the gunfight.