Hadith #4103 (Sunan al-Nasa'i)
Book: The Book of Fighting [The Prohibition of Bloodshed]
Narrator(s): al-Azrq bin Qays al-Harithy الأزرق بن قيس الحارثي, Hammad bin Salama حماد بن سلمة, Muhammad bin Ma'mar bin Rabi' محمد بن معمر بن ربعي القيسي البحراني, Shryk bin Shhab al-Harithy شريك بن شهاب الحارثي البصري, Sulaiman bin Da'ud bin al-Jarud سليمان بن داود أبو داود الطيالسي

“The Messenger of Allah  said: ‘Whoever is killed defending his wealth and is killed unjustly, he is a martyr.'”

Source: https://parallelquran.com/hadith/sunan-al-nasai-4103/