A year after the attack, primary teacher Alison Moore (right) is still unable to return to her south London school and lives in a safe house with police protection.
"Alison is a continuing victim," said Detective Inspector Rodney Burge of Lewisham police, who is leading the inquiry. "She is also a teacher, the backbone of society. I am determined to send out the right message that racism will not be tolerated.
"Someone knows who did this. If those people have no public conscience we hope, by offering money, they may find a material conscience."
A year ago this week Ms Moore was set upon by four white youths as she finished some late-night marking at Sandhurst junior school in Catford, just a few miles from where black A-level student Stephen Lawrence was murdered.
The gang of four screamed racist abuse as they kicked and beat her, then dragged her into nearby bushes - leaving her for dead.
She spent a week in intensive care, suffering from a cracked pelvis, internal bleeding and fractured ribs.
Since then, Ms Moore has been subjected to a racist terror campaign. She was threatened by a masked man who broke into her kitchen at 2am and received death threats warning her to stay out of school or "next time it's the morgue".
One letter, addressed to a nearby school, said: "This is a final warning. Get out of school where you should not be. As a nigger you have no right to be in a school." The note was signed BNP (British National Party).
Despite widespread inquiries police are still no nearer to solving the crimes. Detective Inspector Burge said: "The people who sent the notes may not be the same people who carried out the first attack. These racists are like sex offenders. Once you start delving you realise they are wandering around all over the community.
"I think they will be proud of what they have done and will have boasted about it."
In a TES interview last year Ms Moore said her number one priority was to get back to school. But, she remains on full-time sick leave.
The police reward is in addition to pound;1,000 offered by Lewisham council.