The one who dug the lahd in the grave of the Messenger of Allah ﷺ was Abu Talha, and the one who placed the velvet cloak beneath him was Shaqran, the freed slave of the Messenger of Allah ﷺ.Jafar said, Ubaydullah bin Abu Rafi informed me, saying, I heard Shaqran say, "By Allah, it was I who placed the velvet cloak beneath the Messenger of Allah ﷺ in the grave."
حدثنا زيد بن أخزم الطائي البصري حدثنا عثمان بن فرقد قال سمعت
الذي ألحد قبر رسول الله ﷺ أبو طلحة والذي ألقى القطيفة تحته شقران مولى رسول الله ﷺ قال جعفر وأخبرني عبيد الله بن أبي رافع قال سمعت شقران يقول أنا والله طرحت القطيفة تحت رسول الله ﷺ في القبر
No references are available.
[Hasan]Uthman bin Farqad is hasan al-hadith, and Ibn Abu Rafi is Ubaydullah. Abu Hatim rejected this hadith as unsound, as noted in Ilal al-Hadith, no. 1054.