Detectives questioning man over the murder of Preston mum-of-one Rosie Darbyshire have a limited amount of time to interview the suspect before a charging decision is made.
Under the current law, police have 24 hours from the time of the arrest before officers have to charge the person arrested with a crime or release them.
Read more>>> Preston family's heartbreaking tributes to 'goofy and crazy' Rosie Darbyshire
However, in the case of a serious crime, including murder, police can apply to hold the suspect for up to 96 hours.
If it is decided there is not enough evidence for a charge to be made, police can decide to release a suspect on police bail.
Read more>>> Everything we know so far about the Preston murder investigation
The 25-year-old man arrested yesterday morning on suspicion of Ms Darbyshire's murder has been in custody since around 9.30am on Thursday.
The family of Ms Darbyshire have paid a heartbreaking tribute to their "talented crazy, goofy Rosie".
The 27-year-old, from Ribbleton died as a result of serious head injuries after police were called to the Moor Nook area in the early hours of this morning.
Paying tribute to her, Rosie’s family said: “It doesn't seem real that our crazy, wig-wearing, talented, goofy Rosie won't be bursting through the door in song anymore."