The Seattle Police Department is still investigating three North End cases, including the assault of a University District woman with a hammer, a gang-related shooting of a middle-schooler near Northgate Mall and the stabbing death of a man found on Greenwood Avenue North.WAITING FOR TEST RESULTSIn the case of the Jan. 8 assault of a woman in the University District, the police are awaiting the test results on three hammers, a robbery-demand note and a cellular phone found in the home of a 24-year-old man who had already been charged with two other U-District robberies.Police had served a King County Superior Court search warrant on the man's home in the 5000 block of 15th Avenue Northeast, where they also found a jacket similar the one worn by the attacker in the January incident. The suspect's physical description also is similar to that of the woman's attacker.The man was arrested Jan. 30 for allegedly robbing a pizza-delivery man with a folding knife and for allegedly robbing a Subway restaurant. He was released on Feb. 19.In the Jan. 8 incident, a 22-year-old University of Washington engineering student was attacked with a hammer during a robbery attempt as she was parking her car in the 1800 block of Northeast 47th Street around 6:45 a.m. After trying to get help following the attack, she drove to the UW's north entrance to ask for assistance there. LOOKING FOR SHOOTERThe police department's Gang Unit is investigating the shooting of a 15-year-old Whitman Middle School eighth-grader outside Northgate Mall on Friday, Feb. 22, around 6:15 p.m.According to various news reports, the boy was walking with two friends through the mall's southeast parking lot when three men in their late teens to early 20s approached them. An argument ensued over their involvement in two separate disputes in the mall, and one of the suspects fired seven or eight shots, two of which hit the boy in the leg and groin.The boy is expected to survive his injuries.Mall surveillance footage was given to police to identify the suspects.UNANSWERED QUESTIONSA stabbing victim found in the 10300 block of Greenwood Avenue North on Feb. 21 was identified as William F. Ball, 29, a convicted felon who was cleared as a person of interest in the New Year's Eve stabbing death of Capitol Hill resident Shannon Harps.There are no suspects, nor could it be determined how Ball, who had a history of drug use and violence against women, got to the location. One police officer said he saw Ball at North 105th Street and Greenwood Avenue North minutes earlier, according to the police report.A nearby resident had heard someone hitting the ground hard around midnight and found Ball in a pool of blood. Ball's fall was forceful enough to dislodge some of his teeth, which remained in the ground hours later, according to news reports.Ball had been stabbed in the left chest and could not be revived.[[In-content Ad]]