It was the practice of the Prophet (peace and blessings be upon him):
"When He (peace and blessings be upon him) walked, he would not turn to look behind him."
Hadith Referenceصحیح الجامع الصغیر / حرف الكاف / 4870
Hadith Gradingالألبانی:صحيح
Hadith Takhrij[ابن سعد الحكيم ابن عساكر] عن جابر. الصحيحة ٢٠٨٦.