Phone snatched 4 years ago

This event took 4 years ago. My elder sister was walking at around 7-8 evening while a guy on bike came from the back and snatched her phone.

While doing this, he fell down and the people nearby took the thief to Police station. My sister didn't want to go nor file a complaint just to not create a mess out of it, but the police was reluctant and hence an FIR was made and they took her phone for the evidence and never returned back. My father was there for the whole day to collect her phone 4 years ago and they didn't, so she left it there.

It's been 4 years of this, and now the police are calling back to back to my sister saying 'she has to SUMMON' in court to close this case. She's been saying no to this, she doesn't wanna appear in court and THAT they can keep her phone. They've been asking to submit documents and stuffs with her money for this.
It's been freaking 4 years, she has forgotten this nightmare long ago until now, and the police reached today at our old address, and one of the person informed us about this. How can she get out of this?

She doesn't wanna appear in court. Is there something she can do about it? Because at this point, this is a harassment from the police and doing these things, that too after 4 years.
(And she never got her phone back or even a call back from the police in last 4years)