Prophet Salih said,

﴿قَدْ جَآءَتْكُم بَيِّنَةٌ مِّن رَّبِّكُمْ هَـذِهِ نَاقَةُ اللَّهِ لَكُمْ ءَايَةً﴾

("Indeed there has come to you a clear sign from your Lord. This she-camel of Allah is a sign unto you;'') meaning, a miracle has come to you from Allah testifying to the truth of what I came to you with. Salih's people asked him to produce a miracle and suggested a certain solid rock that they chose, which stood lonely in the area of Hijr, and which was called Al-Katibah. They asked him to bring a pregnant camel out of that stone. Salih took their covenant and promises that if Allah answers their challenge, they would believe and follow him. When they gave him their oaths and promises to that, Salih started praying and invoked Allah (to produce that miracle). All of a sudden, the stone moved and broke apart, producing a she-camel with thick wool. It was pregnant and its fetus was visibly moving in its belly, exactly as Salih's people asked. This is when their chief, Jundu` bin `Amr, and several who followed him believed. The rest of the noblemen of Thamud wanted to believe as well, but Dhu'ab bin `Amr bin Labid, Al-Habbab, who tended their idols, and Rabbab bin Sum`ar bin Jilhis stopped them. One of the cousins of Jundu` bin `Amr, whose name was Shihab bin Khalifah bin Mikhlat bin Labid bin Jawwas, was one of the leaders of Thamud, and he also wanted to accept the message. However, the chiefs whom we mentioned prevented him, and he conceded to their promptings. The camel remained in Thamud, as well as, its offspring after she delivered it before them. The camel used to drink from its well on one day and leave the well for Thamud the next day. They also used to drink its milk, for on the days she drank water, they used to milk her and fill their containers from its milk. Allah said in other Ayat,

﴿وَنَبِّئْهُمْ أَنَّ الْمَآءَ قِسْمَةٌ بَيْنَهُمْ كُلُّ شِرْبٍ مُّحْتَضَرٌ ﴾

(And inform them that the water is to be shared between (her and) them, each one's right to drink being established (by turns)) ﴿54:28﴾ and,

﴿هَـذِهِ نَاقَةٌ لَّهَا شِرْبٌ وَلَكُمْ شِرْبُ يَوْمٍ مَّعْلُومٍ﴾

(Here is a she-camel: it has a right to drink (water), and you have a right to drink (water) (each) on a day, known) ﴿26:155﴾ The camel used to graze in some of their valleys, going through a pass and coming out through another pass. She did that so as to be able to move easily, because she used to drink a lot of water. She was a tremendous animal that had a strikingly beautiful appearance. When she used to pass by their cattle, the cattle would be afraid of her. When this matter continued for a long time and Thamud's rejection of Salih became intense, they intended to kill her so that they could take the water for themselves every day. It was said that all of them (the disbelievers of Thamud) conspired to kill the camel. Qatadah said that he was told that, "The designated killer of the camel approached them all, including women in their rooms and children, and found out that all of them agreed to kill her.'' This fact is apparent from the wording of the Ayat,

﴿فَكَذَّبُوهُ فَعَقَرُوهَا فَدَمْدمَ عَلَيْهِمْ رَبُّهُمْ بِذَنبِهِمْ فَسَوَّاهَا ﴾

(Then they denied him and they killed it. So their Lord destroyed them because of their sin, and made them equal in destruction!) ﴿91:14﴾, and,

﴿وَءَاتَيْنَا ثَمُودَ النَّاقَةَ مُبْصِرَةً فَظَلَمُواْ بِهَا﴾

(And We sent the she-camel to Thamud as a clear sign, but they did her wrong.) ﴿17:59﴾ Allah said here,

﴿فَعَقَرُواْ النَّاقَةَ﴾

(So they killed the she-camel) Therefore, these Ayat stated that the entire tribe shared in agreeing to this crime, and Allah knows best.