Jami` at-Tirmidhi Book 10, Hadith 74
"Umm Sa'd died while the Prophet was absent. So when he arrived he performed Salat over her, and a month had already passed."
Ash-Sha'bi said: "I was informed by one who saw the Prophet: He (pbuh) saw a solitary grave, s he lined his Companions (behind him) to pray over it." It was said to him (Ash-Sha'bi): "Who informed you?" He said: "Ibn Abbas."
the Prophet said: "Indeed your brother An-Najashi has died. So stand to perform Salat for him." He (Imran) said: "We stood and lined up just as the deceased is lined up for, and we prayed for him just as the deceased is prayed for."