Ibn Ishaq (may Allah have mercy on him) said: The order concerning Ibn Abi Sarh was given only because he had accepted Islam and used to write down the revelation for the Messenger of Allah (peace and blessings be upon him); then he went back to being a polytheist and joined (the people of) Makkah. And the order to kill Abdullah bin Khatal was given only because he had been a Muslim: the Prophet (peace and blessings be upon him) sent him to collect zakah and sent a man of the Ansar with him, and he had with him a Muslim freed slave who served him. He stopped at a halting place and ordered the slave to slaughter a goat and prepare food for him. He went to sleep, and when he woke up the slave had not prepared anything for him, so he attacked him and killed him, and then apostatised and became a polytheist. He had a singing girl and her companion, who used to sing satirical verses against the Prophet (peace and blessings be upon him), so he (peace and blessings be upon him) ordered them to be killed along with him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب المرتد / 16880