Police are currently investigating all information that was gathered the past few days. In order to get a good overview of all relevant information, analysts and detectives are running through all statements in combination with technical information such as information retrieved from telephones from the victims and the suspect who was apprehended.
Furthermore new witnesses were questioned today. This process may go on for a few more days since, based on statements of earlier witnesses, other names of possible witnesses come up. Besides that, a vast amount of video-footage has to be studied for all relevant details. Police retrieved camera footage from over 10 locations. This all has to be studied which is time consuming.
The prosecution is preparing requests for assistance to the US authorities. Especially information on the background of the victims and from people close to the victims could be relevant for the investigation. This is where the help of the FBI could come in and would make these investigations go faster and smoother.