Majma al-Zawaid 2650 — Recitation in prayer

Humayd bin Hilal relates: Hisham bin Amir came to the prayer. He came walking quickly and joined the prayer while he was out of breath, and he began reciting aloud behind the imam. When he completed his prayer, it was said to him: "Do you recite behind the imam?" He said: "We do so."
Al-Tabarani recorded it in al-Mu'jam al-Kabir, and its narrators have been declared trustworthy.