Can the President Kill People?

The short and simple answer is yes. The various authorities and means available to him are as diverse and varied as our government agencies.  Most obviously as Commander in Chief the president commands the military.  The military will carry out his orders. The military should also record his orders and report the consequences.  Such reports should be available for review by authorized persons making it likely that they will become public.

The military has overcome this oversight in the past by various well known mechanisms. One legendary example was the order to troops in the Pacific to feed captives from their own rations. Another is to maintain favored units or individuals who well understand that their privileges depend on obedience and discretion. More normally certain areas or endeavors are categorized as off limits and subject to summary execution.

J. Edgar Hoover was a remarkable instance.  His homosexuality made him so vulnerable that he would carry out any executive order.

The National Security Agency, now under military authority can carry out any activity approved by a rubber stamp court.  Richard Nixon crossed the line when he was caught using NSA authority in his political campaign. At that time the NSA was overseen by a committee rather than a court.

Outside the vast array of military intelligence groups there are seven known US intelligence agencies. The Central Intelligence Agency is unique in the world as the only government agency chartered to operate without pretext or legal protection.   Their direction is to not get caught.

 The national police agencies include the Treasury, US Marshals, Drug Enforcement Agency, the aforementioned FBI, Forestry and the new TSA.

It seems reasonable given this assortment that the president could find someone to do his bidding.

Kennedy maintained relationships with gangsters, presumably under NSA authority, George W. Bush found it necessary to circumvent review of some of his projects and Franklin Roosevelt worked with British intelligence. Whatever the means, one would think that a reasonably competent government executive could have as much effectiveness as a corporate leader.

Apparently they just noticed that there is a black guy operating the crane.