While the injury on their heads was that of something like a golf club, the neck wounds were inflicted using a sharp-edged thing like a surgical knife, GFSU Director Mohendra Singh Dahiya told the court.
The injury marks indicated that their throats were slit after the murder, he added.
"I don't know who was attacked first, but they were certainly killed on Aarushi's bed. A golf club, or any similar thing like a hockey stick, was used for the murder, after which their throats were slit using some sharp-edged thing like a surgical knife," he told the court.
After killing Hemraj, the murderers took his body on the terrace in a bed sheet, during the course of which one of them lost control, leading to blood-stained hand marks on the wall along the terrace door.
Dahiya told the court that GFSU joined the investigations after being approached by CBI in October 2009.
The court later fixed April 11 for the next hearing of the case.