G.R. No. L-6687 y L-6688 - Republic vs. Ang Cho Kio

On or about December 30, 1952, aboard Philippine Air Lines plane PI-C-38 enroute from Laoag to Aparri and while flying over Mountain Province:

The accused, Ang Cho Kio (alias Ki Wa, Lucio Lee, Philip Ang, Mr. Ang, Go Ong, Mr. Ong), armed with .45 and .38 caliber pistols, shot Eduardo Diago, the purser, inflicting a fatal wound; and
In a separate incident on the same flight, the accused compelled pilot Pedro Perlas to change the aircraft’s course to Amoy and, upon the pilot’s refusal, shot and killed him.

The accused was informed of two complaints (Criminal Cases Nos. 419 and 420) and, with counsel, pleaded guilty to both charges (murder and coercion with death).
In Case No. 419 (Diago): The court imposed twelve (12) years of minimum prision mayor to twenty (20) years of maximum reclusion temporal, plus indemnity of ₱6,000 to Diago’s heirs and costs.
In Case No. 420 (Perlas): The court imposed reclusion perpetua, plus indemnity of ₱6,000 to Perlas’s heirs and costs.
Motions for reconsideration, arguing that reclusion perpetua (first cause) and death penalty (second) should have been imposed, were denied.
The Provincial Fiscal appealed, contending that (a) in the first cause, premeditation unmitigated by the confession warranted reclusion perpetua; and (b) in the second cause, the act constituted complex crime of grave coercion with murder meriting death.

Whether in the first cause the aggravating circumstance of premeditation is compensated by the mitigating circumstance of spontaneous confession and thus requires reclusion perpetua under Art. 248 of the Revised Penal Code.
Whether in the second cause the accused’s two successive acts (coercion and killing) form a complex crime under Art. 48 of the Revised Penal Code, justifying the death penalty.
Whether the prosecution (People of the Philippines) may appeal to increase the penalty without violating the Double Jeopardy Clause.