AOG
The leaders of the three main parties are extremely busy right now. They cannot be expected to drop what they're doing (establishing the new Government to lead the country for the next half decade), because of a murder.
Whilst they are the process of thrashing out a deal, the police will investigate the crime.
Once a new Government is in place, them it will be down to THAT team to tackle youth crime, the economy, NHS funding, withdrawal from Iraq, transport infrastructure, immigration policy, pension shortfalls and everything else a Goverment has to deal with.
Not sure why you posted the question at this time.