Horace Danby, the protagonist of the story "A Question of Trust," became an assistant librarian in the prison due to a series of events. The story begins with Horace working as a burglar who steals valuable items from wealthy individuals. However, he has a change of heart and decides to return the stolen items anonymously. This act of repentance catches the attention of a wealthy woman named Miss Marcy, who hires him to be her librarian.

1. Horace's initial job as a burglar
Horace Danby's initial job was as a burglar who stole valuable items from wealthy individuals. He had a reputation for being a skilled thief and was able to carry out his crimes without getting caught.

2. A change of heart
After years of stealing, Horace had a change of heart and decided to return the stolen items anonymously. He wanted to make amends for his past actions and start living a more honest life.

3. Catching the attention of Miss Marcy
Horace's act of repentance caught the attention of Miss Marcy, a wealthy woman who was impressed by his honesty and integrity. She offered him a job as her librarian, which he accepted.

4. Being caught by the police
Unfortunately, Horace's past caught up with him when the police discovered that he had been involved in a burglary. He was arrested and sent to prison.

5. Becoming an assistant librarian in the prison
While in prison, Horace was given the opportunity to work as an assistant librarian. He was able to use his knowledge and skills to help other inmates and earn a small income.

In conclusion, Horace Danby became an assistant librarian in the prison due to a series of events that began with his decision to return stolen items and his subsequent employment as a librarian for Miss Marcy. Although he was caught by the police and sent to prison, he was able to use his skills to contribute to the prison community and earn a small income.

He came to be an assistant librarian in the prison because of that lady who introduced herself as the owner of the house and ask him to break the safe and give her the jewellery because she forgot the password of the safe.