Khalid ibn Sufyan is portrayed by critics as an innocent person and somehow was killed because of rumours. Hence, the claim by critics was that there was no threat from him. However, we have authentic Hadith reporting that Khalid was not innocent and that he incited other tribes to go at war against the Muslim minority. The following Hadith states that one of the Companion of the Prophet was sent to deal with him – When the companion found Khalid and asked him questions regarding whether it was true that he wanted to go to war against Muhammed (p), Khalid replied affirmatively that he was involved. Hence, the companion killed him:
Narated By ‘Abd Allah b. Unais: The Apostle of Allah (p) send me to Khalid b. Sufyan al-Hudhali. This was towards ‘Uranah and ‘Arafat. He (the Prophet) said: Go and kill him. I saw him when the time of the afternoon prayer had come. I said: I am afraid if a fight takes place between me and him (Khalid b. Sufyan), that might delay the prayer. I proceeded walking towards him while I was praying making a sign. When I reached near him, he said to me: Who are you? I replied: A man from the Arabs; it came to me that you were gathering (an army) for this man (i.e. the Prophet). Hence I came to you in connection with this matter. He said: I am (engaged) in this (work). I then walked along with him for a while.; when it became convenient for me, I dominated him with my sword until he became cold (dead). (Abu Dawud Book 002, Hadith Number 1244)
Ṣafī al-Raḥmān Mubārakfūrī
THE MOBILIZATION OF ABDULLAH BIN UNAIS
On the fifth day of the same month Muharram, 4 A.H., it was reported that Khalid bin Suyan Al-Hudhali was gathering some mob to raid the Muslim positions. Abdullah bin Unais, at the order of the Prophet set out to destroy the enemies. The Muslim military leader stayed away for eighteen days during which he successfully fulfilled his task, killed the head of the rebels… 
SOFIAN BIN KHALID
After the reverse at Medina, in the battle of Ohad, large gatherings were organized in various quarters of Arabia against the Moslems. The Bani Lahyan, and other neighbouring tribes, rallied round the standard of their chief Sofian, the son of Khalid, at Orna with the avowed purpose of taking this occasion by the forelock when the tables were turned at Ohad. ‘Mahomet, knowing their movements depended solely upon Sofian, despatched Abdullah ibn Oneis with instructions to assassinate him.’ The accredited envoy volunteered himself for the service, which he accomplished by destroying Sofian by surprise. Neither Ibn Ishak, nor Ibn Hisham, nor Ibn Sad have anything to say about ‘instructions’ for assassination. Abdullah-bin Oneis may have been sent as a spy to reconnoitre the movements of Sofian and his army, or to bring advices concerning him, but it cannot be affirmed that he tutored by Mohammad to assassinate Sofian, even on the supposition that his mission was to kill the latter.
In the case of Sofian there was no perfidy, treachery, or violation of faith, nor was there any permission granted by Mohammad for his assassination. He sent, if it be proved he did (but it is never proved), Abdullah against Sofian who had made every preparation of arms, and who had mustered together several Bedouin tribes to attack Mohammad, to fight and kill him; it was a straightforward course allowed by the usages of the military law. 
Don’t forget to follow Discover The Truth on Facebook and Twitter. PLEASE help spread the word by sharing our articles on your favourite social networks. Thank You! Jazaka’Allahu Khayran.
 Ar-Raheeq Al-Makhtum – The Sealed Nectar: Biography of the Noble Prophet By Safi-Ur-Rahman al-Mubarakpuri, page 297
 A Critical Exposition of the Popular Jihad (Original 1885) – Cheragh Ali page 69 – 71