A man is being questioned by police over the murder of a teenage girl who was stabbed to death on a crowded bus on her way to school.
Police are investigating whether Christina Edkins (16) was targeted in a random attack in Birmingham, England, yesterday morning.
She was killed shortly after she boarded the double decker during the morning rush hour.
Just hours earlier, the teenager had posted some apparently despairing messages on Twitter.
She wrote: "Why can't something go right for once" and her final tweet read: "Don't need anyone to talk to about how I feel just need someone to be lazy with me and watch films and make me laugh."
Police launched a manhunt for a fellow passenger who fled the scene in the wake of her murder, involving police dogs and firearms officers.
A 22-year-old man was later arrested and detained by police following a short chase.
The stabbing came a month after Miss Edkins voiced concerns about a fellow passenger on another bus journey.
On February 8 she told friends on Twitter: "This man is worrying me on the bus keeps getting up and walking up and down stairs, and sitting in different place".
The teenager, a pupil at Leasowes High School in Halesowen, West Midlands, was attacked in front of hordes of commuters at around 7.30am.
Medics who rushed to the scene were unable to save her.
Police officers stood guard at the Edkins' semi-detached house near Birmingham city centre for much of the day while family liaison officers sought to comfort relatives.
Neil Shaw, her headteacher, described Christina as a "bright and popular student much loved by staff and students".