The trials of three men for two separate Suffolk County homicides ended with closing arguments and jury instructions this morning, with both cases expected to go to their respective Superior Court juries by this afternoon.

Summing up the case against SHAWN “SHANKS” DAUGHTRY (D.O.B. 5/14/80) of Roxbury, charged with first-degree murder for the 2007 shooting death of 29-year-old Urel Duncan, Assistant District Attorney Gretchen Lundgren said that Daughtry was bent on retaliating against members of a rival gang when he traveled to Codman Park with a firearm.

“On Sept. 20, 2007, Urel Duncan was doing nothing more than hanging out with friends and family,” Lundgren said. “He did nothing more than live on a street in Academy Homes territory.”

Someone had shot at Daughtry earlier, Lundgren said, and “He had to retaliate against some Academy boys … and the only thing that matters is that [he] retaliates against someone in that territory.”

Prosecutors allege that Daughtry and DEMETRIUS WARDSWORTH (D.O.B. 12/26/88) travelled to Codman Park, fired on Duncan and another man as they sat on a stoop, and then fled the scene on foot. Wardsworth was convicted at a separate trial last year and is currently serving a life term for Duncan’s murder.

The incident was captured on surveillance cameras, Lundgren said, and Boston Police “saturated” the area within seconds of the shooting, speaking with several people in the murder’s aftermath. Of those whom the police approached, the prosecutor said, only two – Daughtry and Wardsworth – were dressed in exactly the same clothing as the assailants in the video: Daughtry wore a black hooded sweatshirt with dark pants and black shoes, while Wardsworth wore a gray hooded sweatshirt over a white T-shirt with dark pants and two-tone shoes.

“Demetrius Wardsworth and the defendant were stopped together after the shooting because they went to do the shooting together,” Lundgren said.

Investigators performed a test that found gunshot residue on Daughtry’s left hand, which Lundgren said was consistent with gripping the murder weapon.

“The person in the black hoodie raises his right hand and brings his left hand over it,” she told jurors.

Lundgren also said that there was no chance the gunshot reside had been transferred to Daughtry by police, handcuffs, or the vehicle in which he was transported because Wardsworth – whose gun, prosecutors say, misfired at the scene – was detained by the same officers in the same circumstances but tested negative for gunshot residue.

“It’s not a coincidence that the defendant had a motive that evening,” Lundgren said. “It’s not a coincidence he was found near the shooting. It’s not a coincidence he was with Demetrius Wardsworth that night. It’s not a coincidence he has the exact same physical characteristics as the gunman. It’s not a coincidence that the gunshot residue on his left hand corresponds with the ballistics evidence and the video.”

Just a few minutes later, Assistant District Attorney Cory Flashner laid out the case against AASIM SMITH (D.O.B. 4/13/92) and EUGENE TEIXEIRA (D.O.B. 3/25/87), both of Chelsea, for the fatal stabbing of 25-year-old Cleo “Shadeed” Wiggins in the Chester Avenue home they shared with the defendants’ mother.

Smith and Teixeira are charged with second-degree murder for allegedly storming into the apartment on April 29, 2008, arming themselves, and attacking Wiggins as their mother and a family friend watched in horror.

“Why that day? Because,” Flashner said, “that’s the day their mother kicks them out. That’s the day their mother chooses her boyfriend over her sons.”

The three had argued earlier because Teixeira was not at work, Smith was not at school, and Wiggins told their mother to eject them from the home. The two left the home, Flashner said, only to return with violent intentions.

“When the defendants ran up those stairs and Eugene Teixeira took that knife and plunged it into Shadeed’s body seven times, that’s murder,” Flashner said. “Aasim Smith was there with a baseball bat ready, willing, and able to assist him. He’s aiding and abetting Eugene Teixeira as that happened.”

Flashner disputed the pair’s claim that they were acting in defense of their mother, whom they claimed to have seen leaning out an apartment window screaming for help.

“The window is closed, ladies and gentlemen,” Flashner said. “The screen is shut. The shades are drawn.”

The defendants’ mother can be heard on a 911 tape calling them expletives, telling a dispatcher that they “bum rushed” her boyfriend, and screaming at the youths that they were “going to jail.” Responding Chelsea Police took abundant photos of the mother, none of which show any bruising, swelling, or recent injuries.

“There is no self-defense or defense of another claim if you’re the initial aggressor,” Flashner said. “The evidence shows that clearly. It’s murder in the second degree.”

Jennifer Stott is the victim-witness advocate assigned to the Daughtry trial. Daughtry is represented by attorney Barry Wilson. Judge Frank Gaziano presided over the case in courtroom 906.

Catherine Yuan is the victim-witness advocate assigned to the Smith and Teixeira case. Smith is represented by attorney Stephen Weymouth and Teixeira by attorney George Murphy. Judge Patrick Brady oversaw those proceedings in courtroom 815.