159.    […] As noted by the Trial Chamber, explicit manifestations of criminal intent are, for obvious reasons, often rare in the context of criminal trials. In order to prevent perpetrators from escaping convictions simply because such manifestations are absent, the requisite intent may normally be inferred from relevant facts and circumstances. […]

See also para. 198.

313. The Appeals Chamber recalls that the mens rea of the crime of terror consists of the intent to make the civilian population or individual civilians not taking direct part in hostilities the object of acts of violence or threats thereof, and of the specific intent to spread terror among the civilian population.[1] Such intent may be inferred from the circumstances of the acts or threats of violence, such as, inter alia, their nature, manner, timing, and duration.[2] Nothing precludes a reasonable trier of fact from relying on the same set of circumstances to infer that perpetrators willfully made civilians the object of acts or threats of violence, and, at the same time, that such acts or threats of violence were committed with the primary purpose of spreading terror among the civilian population.

[…] 

315. The Appeals Chamber recalls that terror could be defined as “extreme fear”,[3] and that such fear was merely one of several factors from which the Trial Chamber inferred specific intent in this case.[4] […]